SEASIDE STUDIES IN NATURAL HISTORY. BY ELIZABETH C. AGASSIZ AND ALEXANDER AGASSIZ. MARINE ANIMALS OF MASSACHUSETTS BAY. RADIATES. BOSTON: JAMES R. OSGOOD AND COMPANY, LATE TICKNOR & FIELDS, AND FIELDS, OSGOOD, & CO. 1871. Rntered according to Act of Congress, in the year 1865, by ALEXANDER AGASSIZ, in the Clerk's Office of the District Court for the District of Massaohusetts. UNIVERSITY PRESS: WELCH, BIGELOW, AND COMPANY, CAMBRIDGE. THIS LITTLE BOOK IS AFFECTIONATELY DEDICATED BY THE AUTHORS TO PROFESSOR L. AGASSIZ, WHOSE PRINCIPLES OF CLASSIFICATION HAVE BEEN THE MAIN GUIDE IN ITS PREPARATION. PREFACE. THs volume is published with the hope of supplying a want often expressed for some seaside book of a popular character, describing the marine animals common to our shores. There are many English books of this kind; but they relate chiefly to the animals of Great Britain, and can only have a general bearing on those of our own coast, which are for the most part specifically different from their European relatives. While keeping this object in view, an attempt has also been made to present the facts in such a connection, with reference to principles of science and to classification, as will give it in some sort the character of a manual of Natural History, in the hope of making it useful not only to the general reader, but also to teachers and to persons desirous'of obtaining a more intimate knowledge of the subjects discussed in it. With this purpose, although nearly all the illustrations are taken from among the most common inhabitants of our bay, a few have been added from other localities in order to fill out this little sketch of Radiates, and render it, as far as is possible within such limits, a complete picture of the type. vi PREFACE. A few words of explanation are necessary with reference to the joint authorship of the book. The drawings and the investigations, where they are not referred to other observers, have been made by MR. A. AGASSIZ, the illustrations having been taken, with very few exceptions, from nature, in order to represent the animals, as far as possible, in their natural attitudes; and the text has been written by MRS. L. AGASSIZ, with the assistance of MR. A. AGAssIz's notes and explanations. CAMBRIDGE, May, 1865. NOTE. THIS second edition is a mere reprint of the first. A few mistakes accidentally overlooked have been corrected; an explanation of the abbreviations of the names of writers used after the scientific names has been added, as well as a list of the wood-cuts. The changes which have taken place in the opinions of scientific men with regard to the distribution of animal life in the ocean have been duly noticed in their appropriate place, but no attempt has been made to incorporate more important additions which the progress of our knowledge of Radiates may require hereafter. CAMBRIDGE, January, 1871. CONTENTS. PAGE ON RADIATES IN GENERAL....... 1 GENERAL SKETCH OF THE POLYPS...... 5 ACTINOIDS......... 7 MADREPORIANS..... 16 HALCYONOIDS.........19 GENERAL SKETCH OF ACALEPHS... 21 CTENOPHOR..........26 EMBRYOLOGY OF CTENOPHORE...... 34 DISCOPHORE.... 37 HYDROIDS...... 49 MODE OF CATCHING JELLY-FISHES. 85 ECHINODERMS.. 91 HOLOTHURIANS....95 ECHINOIDS.......... 101 STAR-FISHES........ 108 OPHIURANS......... 115 CRINOIDS........120 EMBRYOLOGY OF ECHINODERMS..... 123 DISTRIBUTION OF LIFE IN THE OCEAN.... 141 SYSTEMATIC TABLE........ 152 INDEX....... 154 LIST OF THE WOOD-CUTS. Unless otherwise specified, the illustrations are drawn from nature by ALEX. AGASSIZ. FIG. PAGE 1. Transverse section of an Actinia (Agassiz)..... 5 2, 3, 4. Actinia in different degrees of expansion (Agassiz). 8 5. METRIDIUM MARGINATUM fully expanded...... 8 6. Vertical section of an Actinia.. 10 7. View from above of an expanded Actinia.. 11 8, 9. Young Actiniae........ 11 10. RHODACTINIA DAVISII.......13 11. ARACHNACTIS BRACHIOLATA........ 14 12. Young Arachnactis....... 14 13. Young Arachnactis showing the mouth...... 14' 14. BICIDIUM PARASITICUM.......15 15. HALCAMPA ALBIDA.......... 16 16. Colony of ASTRANGIA DANA...... 17 17. Magnified individuals of Astrangia.... 17 18. Single individual of Astrangia...... 18 19. Lasso-dell of Astrangia........ 18 20. Limestone pit of Astrangia....... 19 21. Single individual of HALCYONIUM CARNEUM...19 22. Halcyonium community........ 20 23. Expanded individual of Halcyonium..... 20 24. Branch of MILLEPORA ALCICORNIS (Agassiz)...22 25. Expanded animals of Millepora (Agassiz)... 22 26. Transverse section of branch of Millepora (Agassiz)... 23 27. PLEUROBRACHIA RHODODACTYLA (Agassiz)...27 28. The same as Fig. 27 seen in plane of tentacles (Agassiz).. 28 29. Pleurobrachia in motion....... 29 30. Pleurobrachia seen from the extremity opposite the mouth. 30 31. BOLINA ALATA seen from the broad side (Agassiz).... 31 32. Bolina seen from the narrow side (Agassiz). 31 33. IDYIA ROSEOLA seen from the broad side (Agassiz).. 32 34. Young Pleurobrachia still in the egg.....35 35. Young Pleurobrachia swimming in the egg.... 35 36. Young Pleurobrachia resembling already adult... 35 37. Young Idyia....... 35 38. Young Idyia seen from the anal pole..... 36 LIST OF THE WOOD-CUTS. ix 39. Idyia somewhat older than Fig. 37....36 40. Idyia still older.... 36 41. Young Bolina in stage resembling Pleurobrachia... 37 42. Young Bolina seen from the broad side..... 37 43. Young Bolina seen from the narrow side.... 37 44. CYANEA AROTICA......40 45. Scyphistoma of Aurelia (Agassiz)....... 41 46. Scyphistoma older than Fig. 45 (Agassiz).. 41 47. Strobila of Aurelia (Agassiz)..41 48. Ephyra of Aurelia (Agassiz)......42 49. AURELIA FLAVIDULA seen in profile (Agassiz)..42 50. Aurelia seen from above (Agassiz).. 43 51. CAMPANELLA PACHYDERMA....... 44 52. The same from below......44 53. TRACHYNEMA DIGITALE..... 45 54. HALICLYSTUS AURICULA....46 55. Lucernaria seen from the mouth side... 47 56. Young Lucernaria..........48 57. Hydrarium of EUCOPE DIAPHANA.... 50 58. Magnified portion of Fig. 57.....50 59. Part of marginal tentacles of Eucope...... 51 60. Young Eucope..........51 61. Adult Eucope, profile... 51 62. Quarter-disk of Fig. 60........ 51 63. Quarter-disk of Eucope older than Fig. 62. 52 64. Quarter-disk of adult Eucope........52 65. OCEANIA LANGUIDA just escaped from the reproductive calycle. 53 66. Same as'Fig. 65 from below... 53 67. Young Oceania older than Fig. 65..... 54 Diagram of succession of tentacles... 54 68. Adult Oceania.......... 55 69. Attitude assumed by Oceania....56 70. CLYTIA BICOPHORA escaped from reproductive calycle... 57 71. Somewhat older than Fig. 70.......57 72. Magnified portion of Hydrarium of Clytia.. 57 73. Adult Clytia.........57 74. ZYGODACTYLA GROENLANDICA..... 58 75. The same seen in profile...... 59 76. TIMA FORMOSA....... 61 77. One of the lips of the mouth.... 61 78. Head of Hydrarium of Tima........ 62 79. MELICERTUM CAMPANULA from above (Agassiz)..... 63 80. The same seen in profile......... 64 81. Planula of Melicertum.......65 82. Cluster of planule...... 65 X LIST OF THE WOOD-CUTS. 83. Young Hydrarium.. 65 84. DYNAMENA PUMILA........ 66 85. Magnified portion of Fig. 84.... 66 86. DYPHASIA ROSACEA........ 67 87. Medusa of LAFEA...... 67 88. Colony of Coryne mirabilis (Agassiz)...... 68 89. Magnified head of Fig. 88 (Agassiz). 68 90. Free Medusa of Coryne (Agassiz)...... 68 91. TURRIS VESICARIA.......69 92. BOUGAINVILLIA SUPERCILIARIS....... 70 93. Hydrarium of Bougainvillia... 70 94, 95, 96. Medusae buds of Fig. 93...... 71 97. Young Medusa just freed from the Hydroid.. 71 98. TUBULARIA COUTHOUYI (Agassiz)....... 72 99. Cluster of Medusse of Fig. 98 (Agassiz)..72 100. Female colony of HYDRACTINIA POLYCLINA (Agassiz)... 73 101. Male colony of the same (Agassiz)....... 73 102. Unsymmetrical Medusa of HYBOCODON PROLIFER (Agassiz).. 74 103. Medusa bud of Hybocodon (Agassiz)...... 74 104. Hybocodon Hydrarium (Agassiz)...... 74 105. DYSMORPHOSA FULGURANS........75 106. Proboscis of Fig. 105 with young Meduse.... 75 107. Young IANOMIA CARA......76 108. Nanomia with rudimentary Meduse..... 76 109. Nanomia somewhat older than Fig. 108..... 77 110. Heart-shaped swimming bell of Nanomia..... 77 111. Cluster of Medusse with tentacles having pendent knobs.. 78 112. Magnified pendent knob........ 79 113. Medusa with corkscrew-shaped tentacles.... 79 114. Medusa with simple tentacle.. 80 115. Adult Nanomia......... 81 116. Oil float of Nanomia........ 82 117. PHYSALIA ARETHUSA (Agassiz)..'... 83 118. Bunch of Hydre (Agassiz)....... 84 119. Cluster of Meduse (Agassiz)...... 84 120. VELELLA MUTICA (Agassiz)....... 84 121. Free Medusa of Velella (Agassiz).......84 122. PTYCHOGENA LACTEA........ 86 123. Ovary of Ptychogena........87 124. SYNAPTA TENUIS..... 95 125. Anchor of Synapta........96 126. CAUDINA ARENATA........97 127. CUVIERIA SQUAMATA..........98 128. Young Cuvieria......... 99 129. Cuvieria somewhat older than Fig. 128.....99 130. PENTACTA FRONDOSA........ 100 LIST OF THE WOOD-CUTS. xi 131. TOXOPNEUSTES DROBACHIENSIS..... 102 132. Portion of shell of Fig. 131 without spines (Agassiz).. 103 133. Sea-urchin shell without spines (Agassiz)..... 103 134. Sea-urchin from the mouth side (Agassiz)..... 104 135. Magnified spine....104 136. Transverse section of spine...... 105 137. Pedicellaria of Sea-urchin........ 105 138. Teeth of Sea-urchin......... 106 139. ECEINARACHNIUS PARMA........ 107 140. Transverse section of Echinarachnius (Agassiz)... 108 141. Ray of Star-fish, seen from mouth side (Agassiz).... 109 142.' ASTRACANTHION BERYLINUS....... 110 143. Single spine of Star-fish.......111 144. Limestone network of back of Star-fish..... 111 145. Madreporic body of Star-fish...... 111 146. CRIBRELLA OCULATA...... 112 147. CTENODISCUS CRISPATUS........114 148. OPHIOPHOLIS BELLIS......... 115 149. Arm of Fig. 148, from the mouth side'(Agassiz).... 116 150. Tentacle of Ophiopolis........ 116 151. ASTROPHYTON AGASSIZII....... 118 152. Pentacrinus......... 121 153. AECTO MERIDIONALIS......... 122 154. Young Comatulae....... 122 155, 156, 157. Egg of Star-fish in different stages of development. 124 158. Larva just hatched from egg....... 125 159-164. Successive stages of development of Larva....125 165. Larva in which arms are developing..... 126 166. Adult Star-fish Larva (BRACHIoLARIA)..... 127 167. Fig. 166 seen in profile........128 168 - 170. Young Star-fish (Astracanthion) in different stages of development. 129 171. Lower side of ray of young Star-fish...... 130 172. Very young Star-fish seen in profile...... 130 173-175. Larvae of Sea-urchin (Toxopneustes) in different stages of development.... 130, 131 176. Adult Larva of Sea-urchin........ 132 177. Fig. 176 seen endways........ 133 178. Sea-urchin resorbing the arms of the larva.... 133 179 -181. Successive stages of young Sea-urchin... 133, 134 182. Ophiuran which has nearly resorbed the larva.. 135 183. Larva of Ophiuran (Pluteus)....... 136 184. Young Ophiuran......... 137 185. Cluster of eggs of Star-fishes over mouth of parent... 137 Diagram of a rocky beach........ 149 ABBREVIATIONS OF THE NAMES OF AUTHORS. AG... L. Agassiz. JAEG...Jaeger. A. AG.. A. Agassiz. LAM... Lamarck. AYRES.. W.O. Ayres. LAMX... Lamouroux. BLAINV.. Blainville. LIN.. Linnaeus. Boso... Bosc. LYM... Lyman. BR.... Brapdt. M. & T. MiillerandTroschel. CLARK.. H. J. Clark. MILL... Miller. Cuv.. Cuvier.'PER. et LES. Peron and Lesueur. D. & K.. Diiben and Koren. SARS... M. Sars. EDW... Milne-Edwards. STIMP...Stimpson. FORBES.. Edw. Forbes. TIL... Tilesius. GRAY.. J. E. Gray. MARINE ANIMALS OF MASSACHUSETTS BAY. ON RADIATES IN GENERAL. IT is perhaps not strange that the Radiates, a type of animals whose home is in the sea, many of whom are so diminutive in size, and so light and evanescent in substance, that they are hardly to be distinguished from the element in which they live, should have been among the last to attract the attention of naturalists. Neither is it surprising to those who know something of the history of these animals, that when the investigation of their structure was once begun, when some insight was gained into their complex life, their association in fixed or floating communities, their wonderful processes of development uniting the most dissimilar individuals in one and the same cycle of growth, their study should have become one of the most fascinating pursuits of modern science, and have engaged the attention of some of the most original investigators during the last half century: It is true that from the earliest days of Natural History, the more conspicuous and easily accessible of these animals attracted notice and found their way into the scientific works of the time. Even Aristotle describes some of them under the names of Acalephae and Knidae, and later observers have added something, here and there, to our knowledge on the subject; but it is only within the last fifty years that their complicated history has been unravelled, and the facts concerning them presented in their true connection. Among the earlier writers on this subject we are most indebted to Rondelet, in the sixteenth century, who includes some account of the Radiates, in his work on the marine animals of the Mediterranean. His position as Professor in the University at Mont1 2 MARINE ANIMALS OF MASSACHUSETTS BAY. pelier gave him an admirable opportunity, of which he availed himself to the utmost, for carrying out his investigations in this direction. Seba and Klein, two naturalists in the North of Europe, also published at about this time numerous illustrations of marine animals, including Radiates. But in all these works we find only drawings and descriptions of the animals, without any attempt to classify them according to common structural features. In 1776, 0. F. Muller, in a work on the marine and terrestrial faunae of Denmark, gave some admirable figures of Radiates, several of which are identical with those found on our own coast. Cavolini also in his investigations on the lower marine animals of the Mediterranean, and Ellis in his work upon those of the British coast, did much during the latter half of the past century to enlarge our knowledge of them. It was Cuvier, however, who first gave coherence and precision to all previous investigations upon this subject, by showing that these animals are united on a common plan of structure expressively designated by him under the name Radiata. Although, from a mistaken appreciation of their affinities, he associated some animals with them which do not belong to the type, and have since, upon a more intimate knowledge of their structure, been removed to their true positions; yet the principle introduced by him into their classification, as well as into that of the other types of the animal kingdom, has been all important to science. It was in the early part of this century that the French began to associate scientific objects with their government expeditions. Scarcely any important voyage was undertaken to foreign countries by the FreAch navy which did not include its corps of naturalists, under the patronage of government. Among the most beautiful figures we have of Radiates, are those made by Savigny, one of the French naturalists who accompanied Napoleon to Egypt; and from this time the lower marine animals began. to be extensively collected and studied in their living condition. Henceforth the number of investigators in the field became more numerous, and it may not be amiss to give here a slight account of the more prominent among them. Darwin's fascinating book, published after his voyage to the ON RADIATES IN GENERAL 3 Pacific, and giving an account of the Coral islands, the many memoirs of Milne Edwards and Haime, and the great works of Quoy and Gaimard, and of Dana, are the chief authorities upon Polyps. In the study of the European Acalephs we have a long list of names high in the annals of science. Eschscholtz, P4ron and Lesueur, Quoy and Gaimard, Lesson, Mertens, and Huxley, have all added largely to our information respecting these animals, their various voyages having enabled them to extend their investigations over a wide field. No less valuable have been the memoirs of Klliker, Leuckart, Gegenbaur, Vogt, and Haeckel, who in their frequent excursions to the coasts of Italy and France have made a special study of the Acalephs, and whose descriptions have all the vividness and freshness which nothing but familiarity with the living specimens can give. Besides these, we have the admirable works of Von Siebold, of Ehrenberg, the great interpreter of the microscopic world, of Steenstrup, Dujardin, Dalyell, Forbes, Allman, and Sars. Of these, the four latter were fortunate in having their home on the sea-shore within reach of the objects of their study, so that they could watch them in their living condition, and follow all their changes. The charming books of Forbes, who knew so well how to popularize his instructions, and present scientific results under the most attractive form, are well known to English readers. But a word on the investigations of Sars may not be superfluous. Born near the coast of Norway, and in early life associated with the Church, his passion for Natural History led him to employ all his spare time in the study of the marine animals immediately about him, and his first papers on this subject attracted so much attention, that he was offered the place of Professor at Christiania, and henceforth devoted himself exclusively to scientific pursuits, and especially to the investigation of the Acalephs. He gave us the key to the almost fabulous transformations of these animals, and opened a new path in science by showing the singular phenomenon of the so-called "alternate generations," in which the different phases of the same life may be so distinct and seemingly so disconnected that, until we find the relation between them, we seem to have several animals where we have but one. 4 MARINE ANIMALS OF MASSACHUSETTS BAY. To the works above mentioned, we may add the third and fourth volumes of Professor Agassiz's Contributions to the Natural History of the United States, which are entirely devoted to the American Acalephs. The most important works and memoirs concerning the Echinoderms are those by Klein, Link, Johannes Miller, Jager, Desmoulins, Troschel, Sars, Savigny, Forbes, Agassiz, and Liitken, but excepting those of Forbes and Sars, few of these observations are made upon the living specimens. It may be well to mention here, for the benefit of those who care to know something more of the literature of this subject in our own country, a number of memoirs on the Radiates. of our coasts, published by the various scientific societies of the United States, and to be found in their annals. Such are the papers of Gould, Agassiz, Leidy, Stimpson, Ayres, McCrady, Clark, A. Agassiz, and Verrill. One additional word as to the manner in which the subjects included in the following descriptions are arranged. We have seen that Cuvier recognized the unity of plan in the structure of the whole type of Radiates.' All these animals have their parts disposed around a common central axis, and diverging from it toward the periphery. The idea of bilateral symmetry, or the arrangement of parts on either side of a longitudinal axis, on which all the higher animals are built, does not enter into their structure, except in a very subordinate manner, hardly to be perceived by any but the professional naturalist. This radiate structure being then common to the whole type, the animals composing it appear under three distinct structural expressions of the general plan, and according to these differences are divided into three classes, - Polyps, Acalephs, and Echinoderms. With these few preliminary remarks we may now take up in turn these diferent groups, beginning with the lowest, or the Polyps.* * It is to be regretted that on account of the meagre representations of Polyps on our coast, where the coral reefs, which include the most interesting features of Polyp life, are entirely wanting, our account of these animals is necessarily deficient in variety of material. When we reach the Acalephs or Jelly-Fishes, in which the fauna of our shores is especially rich, we shall not have the same apology for dulness; and it will be our own fault if our readers are not attracted by the many graceful forms to which we shall then introduce them. GENERAL SKETCH OF THE POLYPS. 6 GENERAL SKETCH OF THE POLYPS. BEFORE describing the different kinds of Polyps living on our immediate coast, we will say a few words of Polyps in general and of the mode in which the structural plan common to all Radiates is adapted to this particular class. In all Polyps the body consists of a sac divided by vertical partitions (Fig. 1.) into distinct cavities or chambers. These partitions are not, however, all formed at once, but are usually limited to six at first, multiplying A indefinitely with the growth of the animal in /' i f some kinds, while in others they never in- crease beyond a certain definite number. In 9 the axis of the sac, thus divided, hangs a,, i smaller one, forming the digestive cavity, and supported for its whole length by the six primary partitions. The other partitions, though they extend more or less inward in proportion to their age, do not unite with the digestive sac, but leave a free space in the centre between their inner edge and the outer wall of the digestive sac. The genital organs are placed on the inner edges of the partitions, thus hanging as it were at the door of the chambers, so that when hatched, the eggs naturally drop into the main cavity of the body, whence they pass into the second smaller sac through an opening in its bottom or digestive cavity, and thence out through the mouth into the water. In the lower Polyps, as in our common Actinia for instance, these organs occur on all the radiating partitions, while among the higher ones, the Halcyonoids for example, they are found only on a limited number. This limitation in the repetition of identical parts is always found to be connected with structural superiority. The upper margin of the body is fringed by hollow tentacles, each of which opens into one of the chambers. All parts of the animal thus communicate with each other, whatever is introduced at the mouth circulating through the whole structure, Fig. 1. Transverse section of an Actinia. (Agassiz.) 6 MARINE ANIMALS OF MASSACHUSETTS BAY. passing first into the digestive cavity, thence through the opening in the bottom into the main chambered cavity, where it enters freely into all the chambers, and from the chambers into the tentacles. The rejected portions of the food, after the process of digestion is completed, return by the same road and are thrown out at the mouth. These general features exist in all Polyps, and whether they lead an independent life as the Actinia, or are combined in communities, like most of the corals and the Halcyonoids; whether the tentacles are many or few; whether the partitions extend to a greater or less height in the body; whether they contain limestone deposit, as in the corals, or remain soft throughout life as the seaanemone,- the above description applies to them all, while the minor differences, either in the tentacles or in the form, size, color, and texture of the body, are simply modifications of this structure, introducing an infinite variety into the class, and breaking it up into the lesser groups designated as orders, families, genera, and species. Let us now look at some of the divisions thus established. The class of Polyps is divided into three orders,-the Halcyonoids, the Madreporians, and the Actinoids. Of the lowest among these orders, the Actinoid Polyps, our Actinia or sea-anemone is a good example. They remain soft through life, having a great number of partitions and consequently a great number of tentacles, since there is a tentacle corresponding to every chamber. Indeed, in this order the multiplication of tentacles and partitions is indefinite, increasing during the whole life of the animal with its growth; while we shall see that in some of the higher orders the constancy and limitation in the number of these parts is an indication of superiority, being accompanied by a more marked individualization of the different functions. Next come the Madreporians, of which our Astrangia, to be described hereafter, may be cited as an example. In this group, although the number of tentacles still continues to be large, they are nevertheless more limited than in the Actinoids; but their characteristic feature is the deposition of limestone walls in the centre of the chambers formed by the soft partitions, so that all the soft partitions alternate with hard ones. The tentacles, al ACTINOIDS. 7 ways corresponding to the cavity of the chambers, may be therefore said to ride this second set of partitions arising just in the centre of the chambers. The third and highest order of Polyps is that of the Halcyonoids. Here the partitions are reduced to eight; the tentacles, according to the invariable rule, agree in number with the chambers, but have a far more highly complicated structure than in the lower Polyps. Some of these Halcyonoids deposit limestone particles in their frame. But the tendency to solidify is not limited to definite points, as in the Madreporians. It may take place anywhere, the rigidity of the whole structure increasing of course in proportion to the accumulation of limestone. There are many kinds, in which the axis always remains soft or cartilaginous, while others, as the so-called sea-fans for instance, well known among the corals for their beauty of form and color, are stiff and hard throughout. Whatever their character in this respect, however, they are always compound, living in communities, and never found as separate individuals after their early stages of growth. Some of those with soft axis lead a wandering life, enjoying as much freedom of movement as if they had an individual existence, shooting through the water like the Pennatulae, well known on the California coast, or working their way through the sand like the Renilla, common on the sandy shores of our Southern States. ACTINOIDS. Actinia, or Sea-Anemone. (Metridium marginatum EDW.) NOTHING can be more unprepossessing than a sea-anemone when contracted. A mere lump of brown or whitish jelly, it lies like a lifeless thing on the rock to which it clings, and it is difficult to believe that it has an elaborate and exceedingly delicate internal organization, or will ever expand into such grace and beauty as really to deserve the name of the flower after which it has been called. Figs. 2, 3, 4, and 5, show this animal in its various stages 8 MAIUNU ANIMAiLS Off MASSACIUBIUiTS BAY. of texpasioI anid conttraction. Fig 2 represe nts it with all its external ap pt lndages (bflded int,'an\d lthe whlole body tiattened; li,gp 8 the tentaeles' bem to steal out and thi e body rises sli l.tly; in'Pig. 4^ the body has nearly gt aitned its full height, an-id the teto Fig. 2.H,0 ~qg.;3, t i-g. 4,..^ -^:~ —^-/ 1.... ^~~......................, ^\ ^ ~ ~ ~ ~ *' L^)...~..... ~. ~tcteks, tiottgh liby no mt eantls fully spliread, yet iorm a deliea.tt Fig:s 2T 38, 4 Actnia tot direett d fseg ree- l>f xl'rSiot (.:{~ t'. View fisrom at ove of aln ehUifa with all its tenle. expi.d.id i o mijou th, b cil&.sctd'b.nt^S:hap. tfoduls.at extreA mity f' (outhtti a: f l A t r ooud solt}}t, t tl t t tac~l.s t igs, 8, 9. Youig AcVtiuis in. differentt st;age, of growth 12 MARINE ANIMALS OF MASSACHUSETTS BAY. summit to base, and we have two Actinia where there was originally but one. Another and a far more common mode of reproduction among these animals is that of budding like corals. A slight swelling arises on the side of the body or at its base; it enlarges gradually, a digestive cavity is formed within it, tentacles arise around its summit, and it finally drops off from the parent and leads an independent existence. As a number of these buds are frequently formed at once, such an Actinia, surrounded by its little family, still attached to the parent, may appear for a time like a compound stock, though their normal mode of existence is individual and distinct. The Actinia is exceedingly sensitive, contracting the body and drawing in the tentacles almost instantaneously at the slightest touch. These sudden movements are produced by two powerful sets of muscles, running at right angles with each other through the thickness of the body wall; the one straight and vertical, extending from the base of the wall to its summit; the other circular and horizontal, stretching concentrically around it. By the contraction of the former, the body is of course shortened; by the contraction of the latter, the body is, on the contrary, lengthened in proportion to the compression of its circumference. Both sets can easily be traced by the vertical and horizontal lines crossing each other on the external wall of the body, as in Fig. 5. Each tentacle is in like manner furnished with a double set of muscles, having an action similar to that described above. In consequence of these violent muscular contractions, the water im"bibed by the animal, and by which all its parts are distended to the utmost, is forced, not only out of the mouth, but also through small openings in the body wall scarcely perceptible under ordinary circumstances, but at such times emitting little fountains in every direction. Notwithstanding its extraordinary sensitiveness, the organs of the senses in the Actinia are very inferior, consisting only of a few pigment cells accumulated at the base of the tentacles. The two sets of muscles meet at the base of the body, forming a disk, or kind of foot, by which the animal can fix itself so firmly to the ground, that it is very difficult to remove it without injury. It is nevertheless capable of a very limited degree of X IO DACTIr NA. 13 motion, by mllans of the expalnsion and contractt ion of tins flootlike disk.'Thet Actinicx are extrecmecly vora-cious s; they freed on imussels tand cockles, sucking the annimals out of tuheir shllls. Whon in confin.c.ument t the y ny e fed on raw ttat, atnd sBeem to relish it; biut if compelled to do so, they will live on. mort e mettaglre fare, and will even thrtive for a lolg titme onl stuct tfiod as tthy mayty pick up in the wItt.er wthlrc-e they are kept. Itioda'cl-it ta. (Jittodctit.')tuishi A.;.)'Very dif.trent from this is the brightt red lttodactinia (Fig. 10), quite conlmmoln inl the deeper waters of on.r b.ay, while iar. thor xnordli, i'n Main[e, it occurs at low-water mark. Occasio-nally it may be found thrown uip oil our sandy beaches aftolr a. storm, amnd tihen, if it l as not; b1et l too long out of its niative clemenlt, or too seve.rely:buln fed by tho wavts, it will revive oln bneir thrown into a bucket of fresh sca.water, expand to its fitl' siizc, and slsow 11al the bctauty of its nturat coL. 0oring. It; is crownedt wTt'til at wreatht l iof tfick,sot short tentaecltes ( tg:.:o t 10), danld ithou. gh so viei td and bmd right int ctolor, it is not so pret;ty e as e t t more common. A ctinih l marg: i nata, plu eadaaIsi tc fIelers i ill coin oipar iso0l to which the toltacles of the 1ihodactinitt anre ctlum.sy and slowN in th-eir m-ovemeont:s. All Actin~ite are not attached to thoe soil liko those dsclribed above, nor do they all.term'inat. e in muus'ulai footl, soimme hemitt pointled or rolunded at their cxtrex mitre m.i ty a\el m ln.t nmaldic, waillderting about at will. dringil thei'ti wholte liflt tinu others live buried in theC sand oi-und only exten.di.im: tleir toUntauc:.Ies bhi yomd thie limmits: of the hole 0whoere timey immahke tlhtii hobno; wlthile ofht i ms againl lead a parasitic lifi, fiastenihng thmmselves upon. outr larger lig 10, lir>ho~t.e:tinia r ilavr)'isiii Ag.atural si.ize 14 M.AtIN: ANIMALS 0F1 MASAC! USXI'TTS BAY., jellytt-fish, tho e y,^tll-) thoitgl olne is at a. loss to imagine wt a hat sustctantce they (an derive fromi animals having so little solidity, and consistinrg so largely of water. A.raciatet:ti( s (Atrachnacits brachthiiata A, Ai.t.) PF'igi. IL.ZAmong tth nomadic'I"olyps is La small floatintg Actinia, called Arlaclactis, (Fig. 1.,) from its resemblance to a sp ider They iao found in great plenty floating about during the night, feeoling their way i'n every direction by mean. s of their toentacles, whichl are large in proIporion to the size of the animal, few in n1numl;cr, and turnerd tdownvt ard whfn in their natural attitude. The pa-ttitions and the di:gestive cavity on.t closed between themn are short, as will be seen in F.ig.1, when co-mpared to the general ctaity of the body floating balloon-like above ithem.i Around the Fig' l:m outnh is a second row of 4shorter ten"tactls, lbetter seen in a younger specimeni (11ig,. 12)1 This Aetina dif ers firom those described above, in having itwo of the sides flattened, istead of be.ing pcrfectly circular. Looked at from above ( ias in loig.:18) this dift'rmg, 1i. onco in tho diameters is very perccepti:. Wle; there is an, evident tendency towards establishing a longitudinal axis. n thle sea-anemone, this. disposition is only hinted at in the slightly pointed folds or projections on olp)losit sides of thec circle formed by the mouth, wlhich in the Arachnactis are so clongatcd ias to p)roduce at somtlevlwht narrow slit (see Fig. 11, Aichr act bl rachiolata A. A g. greatly tr Agnified. ig. 12, Young Arach.t:uactk, Fig, 3. Y'i.slng Archnactis seel so ats to haOlw the mouth. Bict'1)UM 15 Fig. 13), instead of a: circular opening. The mouth is also at little out of centre, rather tnaret r one Lend of the disk thaln the other. These facts s a-re i.nterestitng, as t showing tghat the tendency towards cstablislhing a balance of parts, as between an tan.tcrlor and posterior extremity, a right and left side, is not fiogot> tenl in thes e lower animals, ti lugh thei organizationl as a. iwhole is based upon ancq equa lity r of parts, adittig neit of os terior and atterior xtextremities, nor of right and left, nor of above and below, in a stlructural sentse. This anitmntal aso presents at set1eming an1lomaly inl the mode of formation of the young tentacles, winch always make their appeara- ce at the osterior exh1tmity of the longitfiudinal axis, ite new one s being4 pXlace d bhid the older ones, instead of alternalting with themt as in. olther Actinite..lbieitdsi. (BiWtidtm famUicusdtms. A.o.) Tfl.e ci" Adilm (i Fi t. t14), our parasitic Actinia, is to be soul ght for in the rmonlth-folds of' the C(yanea, outr commtont latrgo redt Jell.y-ish. In any inoderate.-sized specilmet. of the latter frofl twelve to cighteen inches i nnes diamt eter, we shall be sure to find one or more of these parasites, hidden alway among thie numerous folds of the mouth. The body is long and taperingf, lhaing an aaperttur in tlhe extremnity, the whole a-nimal beintg'ig, 1,4 like an, elongated cone, strongly ribbed fronm apex to base. At the tbase, viz. at the.louth, end, are a few short, stout tentacles. Tlhis A.cetinia is covered with inlmmmerable little tratnsverso wlrilkles (tsee Fit.:14), by:means of whicl t it fastenas itself securely amtong the fluted membra'nes around the imouth of the Jelly-fist. It will livte a con.siderable tile itn confinement, at- talting itself, for its whole lengtth, to tie 9vesse l ilnt wch it its kept, an. d hclinging quite fiXrly if anly attempt is lmade to remove it. Thet g neral color of the body is violet or a brownish red, though the wrinkcles give it a some.Xwhat mottled appearance. Fig. 14, Bicidiumn parasitlcums natural s., 1G6 IMARINE ANMAI.S OF MABSAIUSXi;Fs BAY..t lacan:ipa, (Iftakoimt uthilt, Ao.) Strange to say, the Actinite, whicht live i'n the mud, aro a:molngt thle most beautifully colored of thlese lanimals.'lThey frctqutt tly prepatre their home wNith some ca.re, liingl tlheitr 1hol by metnals of the same secretions which givte th.eir slimy slurthiee to oour collmon Actinite, and thus flormlinlg a sort of tube, into which tfhy retire whenl alalred. lBut if m distutrbed, the y may be seen. at the opeon door of thleir house with their lmany-colored disk and m lottled tentacles exte.ndinilg beyond the al)tert.re, and th]eir nmouth wvide open.>l ai'ting for Nwhat the titde may lbringf them. By tihe play of their tenotacles, thely can. always produce a cllrrent of water about the timout:i, by.manls of which If)od passes into the stomach. We have sa. id ftha.t these animals alre' very brightly colored, bult the little IHa.lcalfid)npa (Fige, 1-.5) b1elo giAng to our coast, is not one of the brillia.ut ones. It is, on the contraryv, at sima.ll inlsignifictallt Actni, rces bing a worlmn, as it burrows its way thlroglht tho sanid. It is of a pale yellowishi color, with whitish warts on the surfihe. AM A I) i I P 0 ItI 1 A N S. Astraingit. (Asuoranet D)anmc Ao.) Ix Fig'uroe 16, we Ohavc time only species of coral g'rowingl so far north as our latitude,. In1deed, it hardly belongs in tlis volaume, since we havet liml ited ourselves to the:tRadiattes of M1assachtlusetts;.Bay, - its tnorthermltlost )bo0ndary beinlg somewhllat to t the l south of 5assactsetts Ba:y, about tho slthores of Long tIslfatd and, on the islantds of Ma:rtlha's Vinleyard d Sound. But we imttrodu e i t there, tlhougih it is not included under our Fig. 15. laatl alnpt aUsbidxatmlat size. AD LE:POJRIANS. 17 title, becaust any account of th I Radiates, friom twichl s.o imp ta-nt a: group as'that of the coralts wats txcluded, would be very incomplet{. Thlls protty coral of T'i. 1t, aour Nlorthl'rn. watere s is no recft-ih u.ler, a d does not extend (farithc 1 sou;t ltan t he f thores o ef N t h tCarot litne oit us'tt l y erstelablishes itsclt t supo b'roklls eirt ariXul-tr )it (Ms g of rocktl l s ying itt shttel tereo ctreeks aned( inlets, l here the l t iottlent actionl - of thl open s,'t ~is ot flt epC Iresen, of one of tImese little com' nitiCs on a rock inay fis e dietected by whlat scums like at, delicate white filh ov er t. is fim is, ho'wever, broken p fbey a a nmb.cr of lnadii ct rcol ros deposi'tne s indt yen reguilan r fiorm (Fig. 20), circul::r it outlineo, hutc divided bnumenroulc s Parti.tiMons r11unning ftioro the out. cer wall to the centre of etvery such. ci0rcl, where i they uni te a: t a littltc wlh ite:s pot ibhrc llbyet h tilt moul.Oth or oratl op'nin.'"' These circles represt, and indeed are( themselvCs thel distinet individuals (Fig.. 17) compI)oshing the coi nnunity, and they l.oolk Mi.7. not unlike the star-shaped pits o0. a coral o head, tatfral med Iby Astra-ans. Unlikec theP nmssi. v compact (indsy of coral, howxever, thu indi ~ vidn-uds nmiliplyb by hudding- fiomn the baIse chie fly, never rising one above thei other, but.spreatding over the surface on wlihicdh they h~.ave estahl:lishC d themselves, a ftew a dditional individuals atrising lctwvccn thoe older ones. JII consequcuco of this mode7 of growth', such a coiniu — iig. 1). Astra{agia co!oynatytrai swiz:. Fltg. 17. Mn'agaile4d intivildais of an AsratgiaIt. cronnrunitry in di tural features, places thnem at the head of tlhelir class. The lnumbert of tentacles throughout this grolup is always eight. They are very cotmplicated (Fig. 2. ), in comlparison with thel tenltacles of the low le orders, being deeply lobed, Fig,, S, inesto;e paUt. of an indiviiual of Asts'ngi.a; nagnific. Fig. 2t. S S.b:gte in tdivltdald of lateyboniu. m seen from aiove1 magn'ificed. 2( MAtRIX NEii ANIMA.LS OF MASSAC-tUSIETS BAY. and fringed around the margin. Our lalcCyonium colmmuities (Fiig. 22) usually live in deep water, Flgt 22 attached to dead shells, tthougha they inay occasion.ally be biound growing at lowI. wat. er mark, but this is very rare. [hey hatve eceived a ratlher Itungubrioils a.tl ltet from the fishermenl, wtho c:all thtensm." deCad..:nme-n.'s fingers," and indeed, whten thte animals ae contract. cd, sutchl commu. ntunity, withi its short branches attacht d to the miain stock, looks not unlike tl~he( stump of a land, wi. th slhort, fitt filgerts. ln such a con.t dition Ithemy are very ugly, thle whole tlmass beinhg somewhai-t, gelatinous in texturnl,andO a dull, yellowish. aink in color. But when the, animals, whlich are capable of great extension, are fillyp spread, as in Fig. 22, such a polyp-stock, has a mossy, tufted 0look, i and is yo meatlns an unsightly object. When tih individ.VTige2o. u tals aret entirely expanded, as in Fig. 23, Bthey be-. come quite t ranspa. re:nt, 1and their internalt stiructure can readily be seen through the walls of the body; we can then. easily distinguish the digestive cavity, suip)ported ior its whole length by the eight radiating part itionsl', as wct'll tas the great size of the main digestive c avitysurrounding ity s Not withstanding the remanrkable I)ow(er of contraction antd dilatation in. the ajnimals t hetlslves, te t tentacles are but slightly con tractile. Thjis kin d of cotmmun ity increases altogether by budding, the individual polyps romaining' more or less united, the tissues of the individuals becomiin.:g thicklcr by the deposition of lime nodules, and thus fbrming a massive sem.mti-cart.darinnous pulp, uniting the whole community. In the neigd.hbhorhood of iP'rovincetown they are very picntiful, and are. foundl all along the shores of our Bay in deep water. Fig. 22, I Ialcyonimmn cv::nmunity; tnatural size. ig3. 3 wlivi:Idult of tHtc yonfum folly expandedtc; mnsagaile.* GENERAL SKETCH OF ACALEPHS. 21 GENERAL SKETCH OF ACALEPHS. IN the whole history of metamorphosis, that wonderful chapter in the life of animals, there is nothing more strange or more interesting than the transformations of the Acalephs. First, as little floating planulae or transparent spheres, covered with fine vibratile cilia, by means of which they move with great rapidity, then as communities fixed to the ground and increasing by budding like the corals, or multiplying by self-division, and later as free-swimming Jelly-fishes, many of them pass through phases which have long baffled the investigations of naturalists, and have only recently been understood in their true connection. Great progress has, however, been made during this century in our knowledge of this class. Thanks to the investigations of Sars, Dujardin, Steenstrup, Van Beneden, and many others, we now have the key to their true relations, and transient phases of growth, long believed to be the adult condition of distinct animals, are recognized as parts in a cycle of development belonging to one and the same life. As the class now stands, it includes three orders, highest among which are the CTENOPHORAB, so called on account of their locomotive organs, consisting of minute flappers arranged in vertical comb-like rows; next to these are the DisCOPHORn, with their large gelatinous umbrella-like disks, commonly called Jelly-fishes, Sun-fishes, or Sea-blubbers, and below these come the HYDROIDS, embracing the most minute and most diversified of all these animals. These orders are distinguished not only by their striking external differences, but by their mode of development also. The Ctenophors grow from eggs by a direct continuous process of development, without undergoing any striking metamorphosis; the Discophorae, with some few exceptions, in which they develop like the Ctenophorse from eggs, begin life as a Hydra-like animal, the subsequent self-division of which gives rise, by a singular process, presently to be described, to a number of distinct Jellyfishes; the Hydroids include all those Acalephs which either pass the earlier stages of their existence as little shrub-like com 22 MARINE ANIMALS OF MASSACHUSETTS BAY. munities, or remain in that condition through life. These Hydroid stocks, as they are sometimes called, give rise to buds; these buds are transformed into Jelly-fishes, which in some instances break off when mature and swim away as free animals, while in others they remain permanent members of the Hydroid stock, never assuming a free mode of life. All these buds when mature, whether free or fixed, lay eggs in their turn, from which a fresh stock arises to renew this singular cycle of growth, known among naturalists as " alternate generations." The Hydroids are not all attached to the ground, - some like the Physalia (Portuguese man-of-war), or the Nanomia, that pretty floating Hydroid of our own waters, move about with as much freedom as if they enjoyed an individual independent existence. As all these orders have their representatives on our coast, to be described hereafter in detail, we need only allude here to their characteristic features. But we must not leave unnoticed one very remarkable Hydroid Acaleph (Fig. 24), not found in our waters, and resembling the'ig. 24' Polyps so much, that it has long been associated with them. The Millepore is a coral, % ~i::g~, /and was therefore the more easily confounded Ii:~? with the Polyps, so large a proportion of:":~ ~ which build coral stocks; but a more minute investigation of its structure (Figs. 25, Fig.. 26) has recently shown that it belongs with t the Acalephs.* This discovery is the more (^^ important, not only as explaining the true poc't flm, sition of this animal in the Animal Kingdom, but as proving also the presence of Acalephs in the earliest periods of creation, since it refers a large number of fossil corals, whose AftzU -^ 1g affinities with the millepores are well under-..... stood, to that class, instead of to the class of Polyps with which they had hitherto been associated. But for this we should have no positive evidence of the existence of Fig. 24. Branch of Millepora alcicornis; natural size. (Agassiz.) Fig. 25. Animals ofM. alcicornis expanded; magnified. a a a small Hydroid, b larger Hydroid, t tentacles, m mouth. (Agassiz.) * See "Methods of Study," by Prof. Agassiz. GENERAL SKETCH OF ACALEPHS. 23 Acalephs in early geological periods, the gelatinous texture of the ordinary Jelly-fishes making their preserva- Fig. 26. tion almost impossible. It is not strange that the.> true nature of this animal should have remained Igj:. so long unexplained; for it is only by the soft >'.j parts of the body, not of course preserved in the ti~. fossil condition, that their relations to the Acalephs t'!\, may be detected; and they are so shy of approach, drawing their tentacles and the upper part of the body into their limestone frame if disturbed, that it is not easy to examine the living animal. The Millepore is very abundant on the Florida reefs. From the solid base of the coral stock arise broad ridges, branching more or less along the edges, the whole surface being covered by innumerable pores, from which the diminutive animals project when expanded. (Fig. 25.) The whole mass of the coral is porous, and the cavities occupied by the Hydrae are sunk perpendicularly to the surface within the stock. Seen in a transverse cut these tubular cavities are divided at intervals by horizontal partitions (Fig. 26), extending straight across the cavity from wall to wall, and closing it up entirely, the animal occupying only the outermost open space, and building a new partition behind it as it rises in the process of growth. This structure is totally different from that of the Madrepores, Astraeans, Porites, and indeed, from all the polyp corals which, like all Polyps, have the vertical partitions running through the whole length of the body, and more or less open from top to bottom. The life of the Jelly-fishes, with the exception of the Millepores and the like, is short in comparison to that of other Radiates. While Polyps live for many years, and Star-fishes and Sea-urchins require ten or fifteen years to attain their full size, the short existence of the Acaleph, with all its changes, is accomplished in one year. The breeding season being in the autumn, the egg grows into a Hydroid during the winter; in the spring the Jelly-fish is freed from the Hydroid stock, or developed upon it as the case may be; it attains its full size in the fall, lays its eggs Fig. 26. Transverse section of a branch, showing pits, a a a a, of the large Hydroids with the horizontal foors. (.dgassiz.) 24 MARINE ANIMALS OF MASSACHUSETTS BAY. and dies, and the cycle is complete. The autumn storms make fearful havoc among them, swarms of them being killed by the fall rains, after which they may be found thrown ~up on the beaches in great numbers. When we consider the size of these Jellyfishes, their rapidity of growth seems very remarkable. Our common Aurelia measures some twelve to eighteen inches in diameter when full grown, and yet in the winter it is a Hydra so small as almost to escape notice. Still more striking is the rapid increase of our Cyanea, that giant among Jelly-fishes, which, were it not for the soft, gelatinous consistency of its body, would be one of the most formidable among our marine animals. Before entering upon the descriptions of the special kinds of Jelly-fishes, we would remind our readers that the radiate plan of structure is reproduced in this class of animals as distinctly as in the Polyps, though under a different aspect. Here also we find that there is a central digestive cavity from which all the radiating cavities, whether simple or ramified, diverge toward the periphery. It is true that the open chambers of the Polyps are here transformed into narrow tubes, by the thickening of the dividing partitions; or in other words, the open spaces of the Polyps correspond to tubes in the Acalephs, while the partitions in the Polyps correspond to the thick masses of the body dividing the tubes in the Acalephs. But the principle of radiation on which the whole branch of Radiates is constructed controls the organization of Acalephs no less than that of the other classes, so that. a transverse section across any Polyp (Fig. 1), or across any Acaleph (Fig. 50), or across any Echinoderm (Fig. 140), shows their internal structure to be based upon a radiation of all parts from the centre to the periphery. That there may be no vagueness as to the terms used hereafter, we would add one word respecting the nomenclature of this class, whose aliases might baffle the sagacity of a police detective. The names Acalephs, Medusse, or the more common appellation of Jelly-fishes, cover the same ground, and are applied indiscriminately to the animals they represent. The name Jelly-fish is an inappropriate one, though the gelatinous consistency of these animals is accurately enough expressed by it; but they have no more structural relation to a fish than to a bird or an insect. GENERAL SKETCH OF ACALEPHS. 25 They have, however, received this name before the structure of animals was understood, when all animals inhabiting the waters were indiscriminately called fishes, and it is now in such general use that it would be difficult to change it. The name Medusa is derived from their long tentacular appendages, sometimes wound up in a close coil, sometimes thrown out to a great distance, sometimes but half unfolded, and aptly enough compared to the snaky locks of Medusa. Their third and oldest appellation, that of Acalephs, - alluding to their stinging or nettling property, and given to them and like animals by Aristotle, in the first instance, but afterwards applied by Cuvier in a more limited sense to Jelly-fishes, - is the most generally accepted, and perhaps the most appropriate of all. The subject of nomenclature is not altogether so dry and arid as it seems to many who do not fully understand the significance of scientific names. Not only do they often express with terse precision the character of the animal or plant they signify, but there is also no little sentiment concealed under these jawbreaking appellations. As seafaring men call their vessels after friends or sweethearts, or commemorate in this way some impressive event, or some object of their reverence, so have naturalists, under their fabrication of appropriate names, veiled many a graceful allusion, either to the great leaders of our science, or to some more intimate personal affection. The Linncea borealis was well named after his famous master, by a disciple of the great Norwegian naturalist; Goethea semperflorens, the ever-blooming, is another tribute of the same kind, while the pretty, graceful little Lizzia, named by Forbes, is one instance among many of a more affectionate reference to nearer friends. The allusions of this kind are not always of so amiable a character, however, -witness the " Buffonia," a low, noxious weed, growing in marshy places, and named by Linnaeus after Buffon, whom he bitterly hated. Indeed, there is a world of meaning hidden under our zoological and botanical nomenclature, known only to those who are intimately acquainted with the annals of scientific life in its social as well as its professional aspect. 4 26 MARINE ANIMALS OF MASSACHUSETTS BAY. C TEN OPHO RAE. THE Ctenophore diffir from other Jelly-fishes in their mode of locomotion. All the Discophorous Medusae, as well as Hydroids, move by a rhythmical rise and fall of the disk, contracting and expanding with alternations so regular, that it reminds one of the action of the lungs, and seems at first sight to be a kind of respiration in which water takes the place of air. The Greeks recognized this peculiar character in their name, for they called them Sea-lungs. Indeed, locomotion, respiration, and circulation are so intimately connected in all these lower animals, that whatever promotes one of these functions affects the other also, and though the immediate result of the contraction and expansion of the disk seems to be to impel them through the water, yet it is also connected with the introduction of water into the body, which there becomes assimilated with the food in the process of digestion, and is circulated throughout all its parts by means of ramifying tubes. In the Ctenophorae there is no such regular expansion and contraction of the disk; they are at once distinguished from the Discophorae by the presence of external locomotive appendages of a very peculiar character. They move by the rapid flapping of countless little oars or paddles, arranged in vertical rows along the surface of the disk, acting indepen dently of each other; one row, or even one paddle, moving singly, or all of them together, at the will of the animal; thus enabling it to accelerate or slacken its movements, to dart through the water rapidly, or to diminish its speed by partly furling its little sails, or, spreading them slightly, to poise itself with a faint, quivering movement that reminds one of the pause of the humming-bird in the air, - something that is neither positive motion, nor actual rest.* These locomotive appendages are intimately connected with the circulating tubes, as we shall see when we examine the struc* The flappers of one side are sometimes in full activity, while those of the other side are perfectly quiet or nearly so, thus producing rotatory movements in every direction. PLEUROBRACHIA. 27 tural details of these animals, so that in them also breathing and moving are in direct relation to each other. To those unaccustomed to the comparison of functions in animals, the use of the word breathing, as applied to the introduction of water into the body, may seem inappropriate, but it is by the absorption of aerated water that these lower animals receive that amount of oxygen into the system, as necessary to the maintenance of life in them, as a greater supply is to the higher animals. The name of Ctenophorae or comb-bearers, is derived from these rows of tiny paddles which have been called combs by some naturalists, because they are set upon horizontal bands of muscles, see Fig. 29, reminding one of the base of a comb, while the fringes are compared to its teeth. These flappers add greatly to the beauty of these animals, for a variety of brilliant hues is produced along each row by the decomposition of the rays of light upon them when in motion. They give off all the prismatic colors, and as the combs are exceedingly small, so that at first sight one hardly distinguishes them from the disk itself, the exquisite play of color, rippling in regular lines over the surface of the animal, seems at first to have no external cause. Pleurobrachia. (Pleurobrachia rhododactyla AG.) Among the most graceful and attractive of these animals are the Pleurobrachia (Fig. 29), and, though not first in order, we will give it the precedence in our description, because it'will serve to illustrate some features of the other two groups. The body of the Pleurobrachia consists of a transparent sphere, varying, however, from the perfect sphere in being somewhat oblong, and also by a slight compression on two opposite sides (Figs. 27 and 28), so as to render its horizontal diameter longer in one direction than in the other (Fig. 30). rig. 27. This divergence from the globular form, so slight - in Pleurobrachia as to be hardly perceptible to the casual observer, establishing two diameters of different lengths at right angles with each other, is equally true of the other genera. It is inter- f esting and important, as showing the tendency in X Fig. 27. Pleurobrachia seen at right angles to the plane in which the tentacles are placed. (Agassiz.) 28 MARINE ANIMALS OF MASSACHUSETTS BAY. this highest group of Acalephs to assume a bi-. lateral character. This bilaterality becomes still more marked in the highest class of Radiates, the Echinoderms. Such structural tendencies in the lower animals, hinting at laws to be more fully X God developed in the higher forms, are always signifi ^If; cant, as showing the intimate relation between all parts of the plan of creation. This inequality of the diameters is connected with the disposition of parts in the whole structure, the locomotive fringes and the vertical tubes connected with them being arranged in sets of four on either side of a plane passing through the longer diameter, showing thus a tendency toward the establishment of a right and left side of the body, instead of the perfectly equal disposition of parts around a common centre, as in the lower Radiates. The Pleurobrachia are so transparent, that, with some preparatory explanation of their structure, the most unscientific observer may trace the relation of parts in them. At one end of the sphere is the transverse split (Fig. 27), that serves them as a mouth; at the opposite pole is a small circumscribed area, in the centre of which is a dark eye-speck. The eight rows of locomotive fringes run from pole to pole, dividing the whole surface of the body like the ribs on a melon. (Figs. 27, 28.) Hanging from either side of the body, a little above the area in which the eyespeck is placed, are two most extraordinary appendages in the shape of long tentacles, possessing such wonderful power of ex tension and contraction that, while at one moment they may bc knotted into a little compact mass no bigger than a pin's head, drawn up close against the side of the body, or hidden within it, the next instant they may be floating behind it in various positions to a distance of half a yard and more, putting out at the same time soft plumy fringes (Fig. 29) along one side, like the beard of a feather. One who has never seen these animals may well be pardoned for doubting even the most literal and matterof-fact account of these singular tentacles. There is no variety of curve or spiral that does not seem to be represented in their evolutions. Sometimes they unfold gradually, creeping out softly Fig. 28. Pleurobrachia seen in plane of tentacles. (Agassiz.) ItU1EUROOBRAOc1A. 29 and slowly frtom a, state of contraction, or again the little ball, hardlty percep.tible against the side of the body, drops suddenly to the bottom of th e tan k in w hi ch...................................................... ftde anr.imalI is gflolating, an0ld one th kllk-is f(Or a rd momntf 1te t so slight is tie trotteadt. like iatt achment, two v. ti al tha itt hasy actualbody; but war tcste little long cr, ofd t rall1 thes filraments t t spread out ay longst omoCntZitallt and t righl9tZ angleVs wth the dgtelf cvty from the sidt of tio thread, it expands to its Afull Ul.'lth tanmd brcadth, and r.csums t i gtrace tf. volutio ns One iword of the intcrnal str uctuc of th so antinm l s, to cxplait its relation to thi external apptencs. he omo nth opens into a wide digestive cavity (Figs. 27, 28), enclwosed between two vcrtica tutbcs. Toward the opposite cend of cthe body these tubes terminate or unite in a singltue-like fi Cil:ca.'J nal, wthich is a rese'roir tas ita owee ofr the cifrculating fluid poure d it;lo it through an opelning F i S t Ntr bottom.: of the digestirvo calvity. Te sfo ill thti digestive cavity becomes liquefied by mingling with the wiater citcrining with it at the mou.t, and, thus prepared, it, passes into this canal, from which, as we slhall presen.ttl)y see, all theo circlabting t tubes ramiflring throuu.hont the body aren fed, Two of these cirulating tubes, or, as they are called frol thle nature of the liquid they contain, clhymiferous:tiubes, are vttry la urpe, sfta.rting horizon1tally and at right angles with the digestive cavity from the point of junetion between the vertical tubes ("i-g. 30) and tthe, canal, Prcsently they give oft' two branches, these againt ramifying in two directions as thley approach the periphlery, so that each one of thel first main tubes has: multiplied to four, Fig, 29. Natural attitude of Pieurobrachia whe n nmotion., 830 tMARItNEM ANIMA.LS OP MTASSACHUS'T S BAY. before its ramifications reach the s'urface, thus making in all eigh:t radialtg tubes. So fa t hes ol the same level; but asl they reatl thoe xperiphe-ry each ot) gives rise to verti t ube: r.e rnning' alonlg the sur-ng i'lce of the body front pole to polc, j'ust x|vithiu thte rows of locoinotivre fringes on the outer surfiacc, and inmmediately connectecd with thm (]igs. 27, 28). A.s in all tl ( Cte(lplhiort, tlhtese fiinges keep a11) a greatty ragnif ttLt; lettir:tg as i.n Fig. 80 4 d lgctigtve cavity. 83 MAlflII:NE ANIMMAL'.rS OF MANSSAACIIUS E. T BAY. with its rapid 1gyrations, its short amlbulllac:ral tulbes, like iammense pou)ttichs (F.ig. Ti ), its latin p)igment s8)pts scattered over the suriatce (.ig. 38), was an earlier istago of tho'rosy-lhut Idyia, whticth glides t tiroughl the water with a scarcely perceptible lmotion. ig. 38. Fig. 39, gs. i8 -40 represent ttho various stages of its growth. lt will be stion how -\very short are the locomotive filnges (Fig. 39) in compa.) risol'w-ithl those of the- full-igrowln ones (liig, 38). It is Fonll in the adult lidyia that these rows'ig'. >,I. * * * attain their ftull height, and the tabes,. Oramitfing' thro-thout tho body (f1ligo o0)), ar c(pl et e td.i h'e-.] oli'.na:, int its caxnly condition recalls the young loaleu. obracfi a. Atl t lhis period t it h the oospaepl ra t id m6tion, and wi tllt somel what nlmorl' fvadvi ccd, loing t'lltailes, IesembRiiUM' th ose of tfrt tieleurobractia i, l t k l oe thlcr appearane ( "ig. 4I.); it. is only at a, later period that the tentacles become cotnin1::.atc, ii whid0 the la.rgo lobes (Pig. 4i2)) so clrac: cri stic of },oil.tia, arc formcd by the elongation of' the oral end of tle body, the auricles becoming more conspictuous a't the same i.g i. $3. Young':!yia see fron th.::1 wa cnrl emlty, iyagr*iidr ai a..i't io-,eTnlg, otler wltter ia in Yig. 86. }ig. 8. tdyla slomewi iat oOlder than Fig. 37, letUeCing us 1.efori:e atr. {ti otlft Fig. 40. 40, Youtg ilyl in whi h tle ambulacral tubes btgin to ramify i I:agifteAd, letter, as bfore, 1)1SCOPtlOB.:. 3o time (Fig. 43). A littleo later the lobes enlallrge the imoveme nts becole ml ore lazy; it assuntt s both in iolrm and ia:ttits the char"> actor of the atdult. liolina. The se:ries of chan.,ges through vwhichlt the Ctellophorat pass Fig. 41. Fig. 4:g. 4.3. are as ro'matrkablo as anl wt shaltl hItavt occasi(l to describe, tthough xot aceoilptnied witll such absolutely dilTb:rc:tt eo:ton ditions of existence. Thoe ompati sont of t ie e'arlierl stnages of lii)t in these anilRmals with their adutflt con.dition is ilnportantt not onl.y withl refe'i.rence to their modte of developlmenul, blit talso becauselo iit gives is csome insi:.ght into thlt relative statdlinlt of()the diftbr'-ent grotps' sittc it shows 1s that crta:i. n t feattturs, p)erm.lancn.t iln the lower groups, are transicunt in tho highetr onCes. A, strikingt instance of tils occurs in the tact meintionetd above thlat ti.outtg tho long ttentacles so characteris tic of' tot adutlt Pl clurobrachia exist. iut tithe younpg Botlitna t'he yi.eld in importattct at, la ter periodt to theo lobes whichl eventually become the preidominant t tand cl arcterist e ic featt'ro of thle lattert'. 1) I S C O() P 1I 0 I- A. T'a.P dis2k of theo Discophior.t is by no melcans so delicate as that of tiho other Jelly-fishs. es It seems itdcd quite solie, atd some:whatt like cartilag e to tie l toutch, anld yet so large a patrt: of its bulk contsists; of warter thal t (yanca, weigtlhing w\ n liv. e l\ about'tlhirty-4ibur pounds, beming left to dry in tile itun:l ir so'X L dtay, was Fig, 41, Y'komtg Bolfisa in stage iresecmbitng Pleurobrachia g i,:artay imagtiied. Fig. 42,'oulng ISolia secn fromn the broad shid, with rutlimen' taown -rit:: anl los; twn.t:sgnie.st, Figf 43, f.'the sl as Fig 42, en fronm the Tnwiw slde. 38 MARINE ANIMALS OF MASSACHUSETTS BAY. found to have lost about - of its original weight, - only the merest film remaining on the paper upon which it had been laid. The prominence of the disk in this group of Jelly-fishes is well characterized by their German name, " Scheiben quallen," viz. disk-medusae. We shall see hereafter that the disk, so large and seemingly solid in the Discophorme, thins out in many of the other Jelly-fishes, and becomes exceedingly concave. This is especially the case in many of the Hydroid Medusae, where it assumes a bell-shaped form, and is constantly spoken of as the bell. It should be remembered, however, in reading descriptions of these animals, that the so-called bell is only a modified disk, and perfectly homologous with that organ in the Discophorae. The Discophorous Medusm are distinguished from all others by the peculiar nature of the reproductive organs. They are contained in pouches (Fig. 50, o, o, o, o), the contents of which are first discharged into the main cavity, and then pass out through the mouth. Pillars support the four angles of the digestive cavity, thus separating the lower from the upper floor of the disk, while the chymiferous tubes (Fig. 50) branch and run into each other near the periphery, forming a more or less complicated anastomosing network, instead of a simple circular tube, as is the case with the Hydroid Medusae. (Fig. 74.) Cyanea. (Cyanea arctica PER. et LES.) In our descriptions of the Discophorae, we may give the precedence to the Cyanea on account of its size. This giant among Jelly-fishes is represented in Fig. 44. It is much to be regretted that these animals, when they are not so small as to escape attention altogether, are usually seen out of their native element, thrown dead or dying on the shore, a mass of decaying gelatinous matter. All persons who have lived near the sea are familiar with the so-called Sea-blubbers, sometimes strewing the sandy beaches after the autumn storms in such numbers that it is difficult to avoid them in walking or driving. In such a condition the Cyanea is far from being an attractive object; to form an idea of his true appearance, one must meet him as he swims along at midday, rather lazily withal, his huge semi-transparent CYANEB. 39 disk, with its flexible lobed margin, glittering in the sun, and his tentacles floating to a distance of many yards behind him. Encountering one of those huge Jelly-fishes, when out in a rowboat one day, we attempted to make a rough measurement of his dimensions upon the spot. He was lying quietly near the surface, and did not seem in the least disturbed by the proceeding, but allowed the oar, eight feet in length, to be laid across the disk, which proved to be about seven feet in diameter. Backing the boat slowly along the line of the tentacles, which were floating at their utmost extension behind him, we then measured these in the same manner, and found them to be rather more than fourteen times the length of the oar, thus covering a space of some hundred and twelve feet. This sounds so marvellous that it may be taken as an exaggeration; but though such an estimate could not of course be absolutely accurate, yet the facts are rather understated than overstated in the dimensions here given. And, indeed, the observation was more careful and precise than the circumstances would lead one to suppose, for the creature lay as quietly, while his measure was taken, as if he had intended to give every facility for the operation. This specimen was, however, of unusual size; they more commonly measure from three to five feet across the disk, while the tentacles may be thirty or forty feet long. The tentacles are exceedingly numerous (see Fig. 44), arising in eight distinct bunches, from the margin of the disk, and hanging down in a complete labyrinth. These animals are not so harmless as it would seem, from their soft, gelatinous consistency; it is no pleasant thing when swimming or bathing to become entangled in this forest of fine feelers, for they have a stinging property like nettles, and may render a person almost insensible, partly from pain, and partly from a numbness produced by their contact, before he is able to free himself from the network in which he is caught. The weapons by which they produce these results seem so insignificant, that one cannot but wonder at their power. The tentacles are covered by minute cells, lasso-cells as they are called, (similar to those of Astrangia, Fig. 19,) each one of which contains a whip finer than the finest thread, coiled in a spiral within it. CYANEA. 41 These myriad whips can be thrown out at the will of the animal, and really form an efficient galvanic battery. Behind the veil of tentacles, and partly hidden by it, four curtains, with lobed or ruffled margins, dimly seen in Fig. 44, hang down from the under surface of the disk. The ovaries are formed by four pendent pouches, placed near the sides of the mouth, and attached to four cavities within the disk. Around the circumference of the disk are eight eye-specks, each formed by a small tube protected under a little lappet or hood rising from the upper surface of the disk. The prevailing color of this huge Jelly-fish is a dark brownish-red, with a light, milk-white margin, tinged with blue, the tentacles and other pendent appendages having a somewhat different hue from the disk. The ovaries are flesh-colored, the curtain formed by the expansion of the lobes of the mouth is dark brown, while the tentacles are of different colors, some being yellow, others purple, and others reddish brown or pink. Strange to say, this gigantic Discophore is produced by a Hydroid measuring not more than half an inch in height when full grown; could we follow tie history of any egg laid by one of these Discophorae in the autumn, and this has indeed been parFig. 45. Fig. 47. Fig. 46 tially done, we should see that, like any other planula, the young hatched from the egg is at first spherical, but presently becomes pear-shaped, and attaches itself to the ground. From the upper Fig. 45. Scyphistoma of a Discophore; Aurelia flavidula. (Agassiz.) Fig. 46. Scyphistoma, older than Fig. 45. (Agassiz.) Fig. 47. Strobila of a Discophore; Aurelia flavidula. (Agassiz.) 6 42 MARINE ANIMALS OF MASSACHUSETTS BAY. end tentacles project (see Fig. 45), growing more numerous, as in Fig. 46, though they never exceed sixteen in number. As it increases in height constrictions take place at different distances along its length, every such constriction being lobed around its margin, till at last it looks like a pile of scalloped saucers or disks strung together (see Fig. 47). The topmost of these disks Fig. 48. falls off and dies; but all the others separate by the deepening of the constrictions, and swim off as little free disks (Fig. 48), which eventually grow into the enormous Jelly-fish /2,a^h described above. These three phases of growth, before the relation between them was understood, have been mistaken for distinct animals, and described as such under the names of Scyphistoma, Strobila, and Ephyra. Aurelia. (Aureliaflavidula PER. et LES.) Another large Discophore, though by no means to be compared to the Cyanea in size, is our common Aurelia (Figs. 49, 50) Its bluish-white disk measures from twelve to fifteen inches in diameter, but its dimensions are not increased by the tentacles, which have no great power of contraction and expansion, and form a short fringe around its margin, widening and narrowing Fig. 49. slightly as the tentacles are stretched or drawn in. It is quite transparent, as may be seen in Fig 49, where all the fine ramifications of the chymiferous tubes, as well as the ovaries, are seen through the vault of the disk. Fig. 50 represents the upper surface, with the ovaries around the mouth, occupying the same position as those of the Cyanea, though they differ from the latter in their greater rigidity, and do not hang down in the form of Fig. 48. Ephyra of a Discophore; Aurelia flavidula. (Agassiz.) Fig. 49. Aurelia seen in profile, reduced. (Agassiz.) AURELIA. 43 pouches. The males and females in this kind of Jelly-fish may be distinguished by the difference of color in the reproductive organs, which are rose-colored in the males, and of a dull yellow in the females. The process of development is exactly the same in the Aurelia as in the Cyanea, though there is a very slight difference in their respective Hydroids. They are, however, so much alike, that one is here made to serve for both, the above figures being taken from the Hydroid of the Aurelia. It is curious, that while, as in the case of the Aurelia and Cyanea, very dissimilar Jelly-fishes may arise from almost identical HyFig. 50. a/'A droids, we have the reverse of the proposition, in the fact that Hydroids of an entirely distinct character may produce similar Jelly-fishes. The embryos or little planulhe, hatched from the Cyanea and Aurelia in the fall, seem to be gregarious in their mode of life, swimming about together in great numbers till they find a suitable point of attachment, and assume their fixed Hydroid existence. The Cyanea, however, when adult, are usually found singly, while the Aurelie, on the contrary, seek each other, and commonly herd together. Fig. 50. Aurelia flavidula, seen from above o mouth, e e e e eyes, mm m m lobes of the mouth, o o o ovaries, t t t t tentacles, w w ramified tubes. (Agassiz.) 44 MAUIIN'E ANIMAL~'S OI MA.SA.C.lSMTHI' BAY. i"]e S.at)l w lla. (Campalndtl pachyderma A. Ao.) The Camipanella (i1,t 531) is a pretty little Jelly-fisl, nolt t'i:,I: la-rger tlan af pin's head, rtc. produced directly front':tt Sil' c~:isga, witflo ut p ssing t:7 of gcrowth it p"!oto. ably remaains attached to rloatis ts k s. It s delte Vthte bell lIeaveding a kina of paragti si tic existenic; biutth as its habits are not aCewu. ratcly known, this cant o t be asserted as a constant fact r5 spscting t hem. Theg t veilS in lhis oJelly-. fi1sh is very large, form-n ing pendentt pouches hlanging fiont the titcular canal (see Figi., 51.), anld ea.vineg buh jut room 70 11tenougl h for t the lpassage of tteh piroboscis betweon tite folds. It m)ay nlot be anliss to introdiuce ]thee a. g.eneral accountl of fthis organ, whlIich occurs itn n:alny of thl Meduse, though it has very dififbrcnt pro... portions in the various kiltnds, ft is a. delicate en mbranlc, han.lq:: i og iox the citrculaar tutbc, so as pjartia Ily to close tlhe onuth of the bell, leaving a larger or snluler opening for the pasamg of the water, which is talcn in.and foirced o'ut again by Lthe alt r.. nate expa'sions and cont ractions of the bell. F.lg, 51 C'atnlla sneeh n t t profilt gr eatly tnagmdfl c~J, Fig: a... sen from'be, wi. O.RCin, 45 Thereare e but fotir chyvifelrous tulbes in t}e Cam patnlla, and four stilff tentacles, which in consequenc of thie pecu.liar character of the veil appear, when the amnimal is scen in profile, to start frito the middle of the disk. The ovaries con-. sist of eight pouchecs, pllaced near tfhc point of jun'ction of the fotur chymiferotus tubes. (Fig. 52.) This little 1,Medusta is of a dark yellowish color with1 browniish ocellated s-pots, scattered profusely over the upper part of the disk. (irce, (T7iachyn-emtna dtigtiade A. At.) Among the Jellyfishers, the position of which is somewhat doubttfl, is the Circe (lig. 53), differing greatly in outline fromn the ordinary Jfelly-.ig, 3 fishcs. As nmay blie se0e...n inr figulre e, w ithe, bell o.ion-s lint; a sndal poru. tion. of the canimalt; it rtis lles in ba sharp cowne o.sn tohf suny srmmhit, thin nt intg out at the lower edgeo, to form the large cavity i' w)hie hc hangs the long proboscis tanld th e eiglt ovaries, four eof whi. Titehneay ie se tten int Fig. 53 crorwded with eggs. The Circe diflbrs!li consistentcy ","'1 well as in florm, from othemr Jelfylishcs.',t is hlard a-nd horny to:the4 toatch, and the veil, u"su.ally so light ansd filmy, is hIero a it hick foldced memrbranec, whiclh't cvcry stroke of the ai-n rmeat forces the water in and out of the canit. It is very activc, 1moving hIy powcrful jerks, each one of ict wIch tiows it Ir on itsa way. It adva.nces usually in straigtht lines; or, if it wishes to chai'tge its direction, it drives fhe water out of thre veil suddetly 1-ig 6. Triwhyneni~sw a dtigitale nb —o.mt t;~Acx-t 0-tca, ilsii~ 46 MARINE ANIMALS 0P MA. SSACIUSITTS BAY. o0 one0 side or the other, so as to shoot off, sometimes at right angles with its former ppath.'our fargo pedmnculat(d eyes, }idden in the figure by the tentacles, stand out prominealttly from the circular tube. -When the animal is in mlotion, thele, teI1tacles are carrtied closely curl ed around thfi edge of the disk, as in IiFig. 58, where the Circe is represented under a nmagnifying power of two and a. half diametters. This Jelly-fish is of a delicate rose color, fithe tentacles assutiu g, however, at dark-ttpurple tin.t at their xtr m.ities -when contracted. I..ttcerlnaria. ({f iclyd'ttus aurictua CIAmrx,) O)en of the prettiest and most gracefidl, as well as o l of the' mos"t common of our Jcllyh4ishes, is theo Lcttceratt ia (Fig. 54). It Fig 6A, lhas such an extraordinary con~...^...........................p cily syt letteal eup or vase, tlractiityr of all its pfars, etdhat it is lops){' the po.inttt of junctiontttl~l be0tween everyt\ b twto scallops bein not easy to descrb it urne ltr anIy definite fosr or possition, since both are conste. t ntly ctaenging but Bperhaps of all it s awioeus at-s tittuds auid outline:s nt o t towrad t m mgr. p of earal t t o i