ALVMNVS BOOK FVND BIOLOGY LIBRARY G NOTES ON BRITISH HYDROID ZOOPHYTES AND OTHER SUBJECTS, Photo by Window &* Grave. Baker Street, W PHILIP JAMES KUFFOKD, F.G.S. NOTES ON BRITISH HYDROID ZOOPHYTES AND OTHER SUBJECTS (POLYZOAN CONCHOLOGICAL & GEOLOGICAL) BY THE I/ATE PHILIP JAMES RUFFORD F.G.S. Published by HIS WIFE EDITED BY SSwocrd fconnold, &&S. Author of " British Vegetable Galls" HASTINGS BURFIELD & PKNNELI.S PRINTERS AND PUBLISHERS MDCCCCII All rights reserved. BIOLOGY 1BRAFN PLATE I. E. C. /V«j/(>. . . .-Folio 25 of RUFFORD'S MS. See p. 20. V. A UTHOR'S PREFA CE. The writer would like at the outset to acknowledge his great indebtedness to Hincks' work on the "Hydroid Zoophytes." He has, however, studied the local species sufficiently carefully in their haunts, and with the microscope, to enable him to write from personal observation. The figures, except those ascribed to other authors, are from sketches from nature by the author. The specimens in the Collection here described (unless otherwise stated) were presented to the Hastings and St. Leonards Museum, in 1899, by the Author. P. J. ETTFFOED. October, 1899. 681S43 VI. INTRODUCTORY REMARKS BY MRS. ALICE RUFFORD. A short description may be desirable to acquaint the reader with the reason which has led me to publish this volume. Some years ago it was resolved by the Committee of the Hastings Museum Association that the exhibits in the various sections should be catalogued. The Hon. Secretary, Mr. Crake, asked Mr. Eufford to begin by making a list of the specimens of the lower forms of Marine Fauna, giving a short description of each. This work he gladly undertook ; but, finding it impossible to compress in a few words such a definition as would be of any use to a student, he produced the following illustrated catalogue which was acquired by the Association, by whom, but for lack of funds it would have been published. That I am now able to do so is owing to the generosity of the Committee in returning me the MS., and I offer them my sincere thanks for their courtesy. I wish also to tender my hearty thanks to Mr. Connold, F.E.S., for undei taking the Editorship, contributing some pages, producing photographs for nineteen plates and relieving me of aJ! care and anxiety ; to Mr. Seward, F.E.S., for his sympathetic Appreciation, and to Dr. Woodward, F.E.S., who kindly obtained permission from the Trustees of the British Museum (South Kensington) to reproduce Plate XXI. ; and lastly to Mr. Crake who constantly helped and encouraged Mr. Eufford in his work, for his kind contribution. Knowing how strongly my late husband was imbued with the idea of the Educational value of Museums, I hope this little tribute to his memory will be found helpful to future students of the extremely beautiful and interesting Marine Fauna and Geology of Hastings. ALICE EUFFOED. 37 MAGDALEN EOAD, ST. LEONARDS-ON-SEA. 1902. vu. EDITOR'S NOTE. It has afforded me a great amount of pleasure to edit this volume at the request of Mrs. Rufford, and I have endeavoured to arrange the material in as suitable a manner as possible. For several years Mr. Rufford, and myself, collected the local Hydromedusse and Polyzoa unknown to each other ; and, while he studied the structure and economy of the creatures and their habitations, with the result shown in the following pages, my researches after a while were directed to other branches of Natural History. Most of the illustrations represent the actual specimens collected by Mr. Rufford, three only are from my own collection; many more could have been added had it been thought desirable. The objects depicted on Plates XII. -XVII. did not possess any other explanations than those which appear in the illustrations. I have therefore ventured to add several pages of descriptions, which, I trust will be useful. Throughout the volume except pp. 123-129 the large type (Pica) represents Mr. Rufford' s writing, the smaller type (Long Primer) that which has been added. Edward Gbnnold. Ylli. CONTENTS. PAGE. Title Page .. .. .. iii. Author's Preface . . . . . . v. Introductory Eemarks by Mrs. Alice Kufford vi. Editor's Note . . . . . . vii. Contents . . . . . . . . viii. List of Plates . . . . . . x. Explanation of Figures . . . . xi. TABLE A.— HYDBOIDA .. .. xiv. Notes on the Work of P. J. Kufford, for the Hastings Museum, by W. V. Crake, B.A. . . . . xv. Introduction by P. J. E. . . . . xix. Fig. 1. — Campanularia flexuom .. .. xxii. Explanation of Fig. 1 . . . . xxiii. TABLE B. — Phases of Reproduction . . xxiv. PART I. The Economy of British Hydroid Zoophytes . . . . 1 TABLE C. — The position of the Hydro- medusse in the Phylum COSLENTERATA 32 CONTENTS. ix. PAET II. An Account of the British Hydroid Zoophytes in the Hastings and St. Leonards Museum . . 35 GLOSSARY . . . . . . 82 Annotations made by P. E. in Hincks' " History of British Hydroid Zoo- phytes " . . . . . 84 PAET in. An Introduction to Polyzoa, or Bryozoa 91 TABLE D.— The Classification of the Phylum POLYZOA . . ' .. 105 PART IV. Conchological Notes . . . . 107 PAET V. An Appreciation. By A. C. Seward, M.A., F.E.S., F.L.S., F.G.S. „ .. 123 The Geology of the East Cliff, Hastings 131 TABLE E. The position of Ru/ordia Gopperti in the Wealden Plants . . 141 Description of RUFFORDIA GOPPERTI .. ., 141 Corrigenda . . . . . . 143 Index . . . . 144 LIST OF PLATES. PHILIP JAMES KUFFOKD, F.G.S. Frontispiece. Plate Facing Page. I. Fac-simile of Folio 25 of P. J. E.'s MS. .. ,. v. II. Tulularia coronata . . . . 44 II. Coryne vaginata . . . . 44 II. Olelia gelaiinosa . . . . 44 IH. Eudendrium ramosum . . . . 46 IV. Tulularia indimsa . . . . 49 V. Sertularia pumila . . . . 69 "VT. Sertula/ria operculata . . . . 70 VII. Sertularia cupressina . . . . 72 VIII. Antennularia antennina . . . . 74 IX. Antennularia ramosa . . . . 76 X. Aglaophcnia pluma . . . . 78 XI. FlusLra foliacea . . . . 91 XI. Lcpralia foliacea .. .. 91 XII. Eostellaria curvirostris . . . . 107 XEH. The Bivalve Shell and its parts . . 109 XIV. The Cartilage, and its arrangement 111 XIV. The Hinge-Teeth .. .. Ill XV. The Animal and SheU-Plates of Chiton 113 XVI. The Animal of Anodonta cygnea . . 115 XVI. The Animal of Buccinum undatum .. 115 XVTI. Branchiae in Lamellibranchiata .. 119 XVHI. The East Cliff, Hastings . . 131 XIX. Diagrammatic Section of the East Cliff 133 XX. Foot-impression of Iguanodon . . 135 XXI. Ruffordia Oopperti . . . . 141 XI. EXPLANATION OF FIGUEES. PAGE. Fig. 1. — An example of a small Hydroid colony (after Hincks) xvi. Fig. 2. — An Athecate, or naked polypite . . 34 Fig. 3. — A Thecaphorean polypite provided with a horny covering, or receptacle . . . . 34 Fig. 4. — The structure of a typical Hydroid (Hydra) and the distinctive difference between Budding and Ova production ; also a dart cell (from Parker and Haswell after Schneider) . . 36 Fig. 5. — Animal of Hydra vulgar is, showing young bud and mature bud ; also dart extruded from its cell 38 Fig. 6. — Diagram to show the nature of " budding " 40 Fig. 7. — Hydr actinia cchinata, showing " select" poly- pite, reproductive buds, tentacular filaments and horny spines. . . . . . . 42 Fig. 8. — Shows a small crustacean pierced by darts of a Hydroid . . . . . . 44 Fig. 9. — Shows a Thecaphore in which the receptacle is produced into points, forming a roof or oper- culum, over the polypite . . . . 46 Fig. 10. — Eeproductive bud with oral tentacles, of Tubularia coronata . . . . . . 50 Fig. 1 1 . — A typical Hydroid with its free Eeproductive bud, or Medusa . . . . . . 54 Fig. 12. — Transverse section of polipary of Coppinia arcta for correlation with crust of Hydractinia (fig. 7), and the section of stem of Antennularia (fig. 13) .. .. .. 64 Fig. 13. — Transverse section of A ntennularia ramosa 75 Fig. 14. — A polypite of Plumularia pinnata expanded and gorging a worm; also enlargements of tentacle and dart cells in situ . . . . 78 Fig. 15. — A polypite of Plumularia pinnata retracted., with " Nematophores " or " Guard " polypites 79 Fig. 16. — Shows the change and atrophy which take place in the " select" polypite in the course of its evolution from the Athecate to the The- caphorean form. Also the point where the fully matured Medusoid fails to be set free 81 .BRITISH HYDROID ZOOPHYTES. XIV. TABLE A. Order I. HYDROIDA. Sub-order I. ATHECATA. Polypites naked — without receptacles. Polypites stalked, branched, and terminal ; (OOEINID^S). Sub-order II. THECAPHORA. Polypites provided with horny receptacles. a Polypites stalked and terminal ; (CAMPANULAEIIMS). b Polypites disposed on both sides of axis ; (SEETULAEIIMS). c Polypites disposed of on one side only of axis ; (PLUMULAEIIDJE). P. J. E. XV. NOTES ON THE WORK OF MR. P. J. RUFFORD FOR THE HASTINGS MUSEUM. In putting these notes together I feel I am perform- ing an urgent duty, the more pressing since during Mr. Rufford's life his innate modesty kept him ever in the background, so that for many years the part which he took in promoting the Hastings Museum was scarcely understood, and his name in Hastings unknown outside a small circle of fellow workers. Mr. Rufford's first connection with the Museum was through the sale of the effects of the late Mr. S. H. Beckles, F.R.S., F.GKS., in April, 1891. The Museum Committee was then fully organised, and a grant had been obtained from the Committee for the purchase of specimens. I was fortunate enough to accidentally meet Mr. Rufford — not knowing him even by name — and seeing him interested in the collection which he was explaining to a boy by his side, I came up and spoke to him, From this chance acquaintance a friendship sprang up between myself and Mr. Rufford, which was fruitful of so much during the last ten years for myself and the Museum. I shall always look with pleasure upon those days, at the same time regretting that they are ended. To return to the Beckles' sale. I then mentioned the position of the Museum Committee as purchaser; and Mr. Rufford gladly consented to give me his advice as to what to purchase. The Beckles' sale was an important step in the history of the Museum, because a home had to be found for the purchases. The Brassey Institute second floor was granted by the Town Council, and a beginning was made. In the minutes of April 2nd, 1892, I find a vote of thanks was passed to Mr. Rufford for his valuable aid in selecting fossils at the Beckles' sale, and again reference is made in the minutes of November 2nd, 1891, to expenses voted for removal of geological remains from Cliff End, Fairlight, to the Brassey Institute. This referred to the Iguanodon foot-print sand- cast now at the Museum which he presented. In October, 1891, the Her. J. W. Tottenham gave his munificent gift of his private Museum to the Museum, and' after the removal which was carried out by me, Mr. Kufford threw himself vigorously into the task of arranging the specimens. Q-eology and Conchology and kindred forms of life had his peculiar care. Con- chology was well represented in the Tottenham collection. At an early stage of the history of the Museum, the Bradnam collection of local fossils from the Town Hall formed part of the original nucleus, to this was added the Beckles^ fossils, mostly from the Wealden strata. A strong reinforcement was now to be added to our local collection by the loan of Mr. Kufford's private collection, which being added to from time to time, has given a marked geological character to the Museum, and caused it to be respected by geologists and men of science who visit the town. At the opening of the Museum in the Brassey Institute, on Tuesday, August 16th, 1892, I made a few remarks from the platform in which after mentioning donors and lenders I said, " I must now turn to those who have given what is perhaps as valuable as money — that is time and dearly-bought knowledge. I must in the first place mention Mr. P. Rufford, our Hastings geologist, a gentleman well known in the scientific world for his researches amongst our Wealden flora ; this gentleman has given up nearly his entire time since the month of May to arranging our specimens, both geological and otherwise. As I have been intimately associated with him during the last few months I can say that our Museum could scarcely have taken shape without his single-minded enthusiasm for science." Mr. Smith Woodward, representing the Geological Department of the British Museum, referred to the discoveries of Messrs. Charles Dawson and Philip Kufford in the Wealden strata, and stated there was evidence that very soon their work would surpass that of Gideon Mantell, the great Sussex geologist. On November 17th, 1893, Mr. Bufford was unani- mously elected a member of the Museum Committee, from which time he became one of its most useful and energetic members, identifying himself thoroughly with its interests, and sparing neither time or trouble in any work he might s»t himself to accomplish. XV11. The collection, including a fine series of Mollusca, was partly the cause that Mr. Rufford directed his atten- tion to this section of Natural History, and to further illustrate the section many shells were added by him. The fishermen took to him specimens which were usually thrown back into the sea after the day's dredging, and by this means a fine collection of Hydroids and Polyzoa was formed, to which the energies of his later years were specially directed. At one time an effort was made to start Aquaria in the Museum. Mr. Rufford did his share of the work with ability, but the difficulty of keeping the water fresh marred his efforts in this direction. It is not necessary to detail the quiet work which Mr. Rufford carried out during the years between 1893 and 1899, making descriptive labels and displaying specimens ; the Museum tells its own tale. But mention must be made of the pictorial work of illustration which he carried out during this period with prints gathered from the British Museum Catalogue of his Wealden flora at the British Museum, and other kindred sources. This was an improvement on the usual methods of labelling, and one much encouraged by the Committee. A recogni- tion of Mr. Rufford's services was made by the Committee during this period by the gift of a standard work on shells which Mr. Rufford much appreciated. In June, 1899, Mr. Rufford finally presented to the Committee the results of his labours. The letter was brief which announced the gift, it contained this passage : ''Dear Crake, Thanks for your note, it may be well to specify the collections which I have the pleasure to offer to the Museum as a gift, viz. : 1. The Geological Collection from the Wealden formation of Hastings and neighbourhood at the Museum up to the present date. 2. Local recent Sponges. 3. Local Hydroids. 4. Local Echmoderms. 5. Local Polyzoa. 6. Local Mollusca. 7. Land and Freshwater Mollusca. (Local and from other Districts British.) " We now approach the last years of this life full of study and joy in the search of the hidden secrets of the earth. Since 1899, Mr. Rufford had been engaged in XV111. work for the Victoria History of the Counties of England, work for a Continental Museum, and in writing and illustrating the catalogues published in this volume, which is elsewhere referred to, also he was busy in the illustra- tion of the Polyzoa and Hydroids to place with his specimens referred to in this volume. In the work of the removal of the collection into its new home on the first floor of the Brassey Institute in 1900, no member of the Committee worked harder than Mr. Rufford. In 1901 the idea was mooted in the Committee of forming a Marine Biological Station in connection with the Museum, and money was voted for the purchase of a trawl net. This had Mr. Rufford's hearty support and during the winter of 1901, he paid a visit to the Marine Biological Station at Naples, purchasing specimens and himself studying on the spot, and visiting the fishing grounds in the steam trawl of the Institution; this resulted in an addition to the treasures of the Hastings Museum of Mediterranean Medusae, etc. Mr. Rufford heartily aided me with the work of demonstrations to schools, and one of his last remarks to me was, that he was very pleased with the boys and girls of Tower Road Board School who were so interested in his last lecture on Geology, as he feared that he had dealt with matters rather above them. The loss to the Museum in the coming years will be great, as they will no longer have the willing aid of Mr. RufEord, one of its best friends, with his large scientific reading and experience which he was ever ready to place at the service of all, and whose place it will be difficult to fill, as such services can only be rendered by one who has been long in sympathetic touch with the Institution in all its aims and endeavours. W. V. CRAKE, Hon. Sec. of the Hastings & St. Leonards Museum Association. ST. LEONARDS-ON-SEA. 1902. INTRODUCTION. The Hydroids are mostly minute creatures and nearly all marine. The individual animal is termed a Polypite. They rank in organization just above the Sponges and below the Sea-anemones and Coral-polyps, to which they are closely allied. Their structure is simple. A sack-like stomach, the only external aperture being the mouth, around which are arranged tentacles armed with poisonous darts or stinging cells, for the capture of prey. The exterior of the body- wall is composed of a cellular layer (Ectoderm), some of the cells of which by extending and withdrawing lobes, perform the office of muscles, of which the Polypites proper are destitute. Within this is a delicate non-cellular membrane (Mesoglaea), the inner lining being composed of a layer of cells (Endoderm), which have the Property of throwing out pseudopodia and agella, by means of which circulation of the food particles is kept up. Some of these cells contain pigment and secrete a digestive fluid. A very few Hydroids (ex. Hydra) lead a solitary existence. The great majority, however, by a plant-like process of continuous budding form colonies, the members of which are all organically connected, by reason of the xx. INTRODUCTION. Buds or newly-formed Polypites not being detached. The connective parts are tubular, and allow the circulation of nutriment to all members of the colony. In nearly all Hydroid colonies there is an outer horny cuticle (the Polypary), which in some cases does not clothe the Polypite itself, but only the connecting parts (the Ccenosarc). These naked Polypites form the division ATHECATA. Those in which the cuticle is prolonged to form protective cups or calycles constitute the division THECAPHORA. The forms of the calycles vary, the rim being either plain, dentate, or with denticles which meet above the polypite and form a lid, or operculum. The arrangement of the calycles on the stem and branches also differs. They may be either terminal (ex. Campanularia), biserial — opposite or alternate — (ex. Sertularia), or uni- serial (exs. S. Plumularia, and Antennularia). In one family of THECAPHORA there are found certain Amoeboid bodies called Nematophores, more or less closely associated with the Polypites, and provided with darts and cuticular receptacles. The functions of these bodies are not known. It is possible that they are to be regarded as modified Polypites. The principle of Alternation of Generation makes its first appearance in the Animal kingdom in this group. The Polypite is not INTRODUCTION. xxi. endowed with the function of sexual reproduction, but certain members produce Special Buds which are so endowed, the bearers of these buds becoming considerably modified in consequence. They are devoid of mouth or tentacles, and so do not concern themselves with procuring food. They are termed Blastostyles. The Special Keproductory Buds, in the lower forms of Hydroids, are liberated as Jelly-fishes, and disperse with their contained ova, to other parts. In the higher forms of Hydroids, these Reproductory Buds remain attached, setting free the ova in situ. Before liberation, the ovum undergoes segmentation, and produces, by a process of inversion, a central cavity — the future stomach. The embryo is termed a Planule, and is provided with cilia, by means of which it swims away, shortly attaches itself to some object, forms rootlets by the splitting up of the expanded base of attachment, and also develops a mouth and tentacles ; it then becomes an ordinary Polypite, which, as growth proceeds, buds and forms a new colony. P. J. K. Fig. 1. XX111. EXPLANATION OF FIG. 1. Fig. 1. Campanularia flexuosa, Hincks. (after Hincks.) A. Natural size of colony. B. A shoot enlarged, bearing B.' Male reproductive capsules. B./; Horny cup or receptacle. B.//; Polypite extended. B.//;/ Polypite retracted. C. A shoot enlarged, bearing C.1 C.' Female or egg-capsules. D. Coenosarc, or connecting tissue which forms a tube. XX.1V. PQ s 1 M'g II e a ' cs Is •a I PHRT 1. THE ECONOMY BRITISH HYDROID ZOOPHYTES. General Remarks. "Things of beauty are generally small," says Aristotle, and the animals here represented, taken individually, are generally so minute that they would probably escape the notice of even the most enthusiastic searcher, did they only occur singly. They, however, have the habit in one of the phases of their existence — the fixed phase — of living collectively or in colonies, and in this form they may be discovered without much difficulty, in rock pools along the sea-shore ; growing amidst the groves and spinneys of seaweed, or upon rocks, seaweed, and shells ; they are also carried about on the coverings of living shell-fish, upon the backs 2 BRITISH HYDKOID ZOOPHYTES. of Crustacea, and, in fact, upon many other creatures and objects. The shrimp trawlers' nets and boats, and the "rubbish" from the larger trawling vessels afford a rich source whence many rare forms may be obtained. Hydroids six-ft. high. If, however, we /were; to look abroad in the Pacific, we . should .find -fixed hydroids of the stature of a man, that is five or six feet high, but those which we are likely to meet with here will generally require the aid of a microscope, in order that their beauty, structure, habits, and remarkable life history may be observed. They are, however, particularly convenient for the microscopist, since they are of so transparent a nature that their internal structure and the operations of digestion and circulation — not to mention the elaborate and interesting stinging apparatus, which the animals use for overcoming their prey — can be readily observed. Some knowledge of each step of the animal kingdom is so necessary as affording the key to other parts, and for a proper comprehension of the whole, that even creatures so low in the scale of organization as the present group, should not be despised. GENERAL REMARKS. 3 If they require any testimonial to recommend them to lovers of nature, it will be sufficient to say that they are very closely allied to the sea-anemones and the polyps, animals which form those exquisite structures the Corals. Hydroids allied to the Sponges and Corals. In organization, the Hydroid animals (or polypites) are a step below these ; but, on the other hand, they have as neighbours below them, though in a separate order, the anomalous group of animals, the Sponges. 4 * Zoophytes," so named by Linnaeus. The group with which we are dealing, in common with others of like form and habit, was styled by Linnaeus " Zoophytes," since, in consequence of the peculiarity they evince of forming tree-like growths and of the resemblance of the animals themselves to flowers, he regarded them as combining the natures of both plants and animals. The cause and nature of these structures will be found a most interesting study. The polypites themselves can hardly be excelled in chaste beauty, being usually of a crystalline transparency sometimes picked out with BRITISH HYDROID ZOOPHYTES. opaque white, or occasionally coloured pink, red, or orange. In the free phase (Medusa) the colouring is more vivid. In form the polypites are particularly elegant, and have only to be seen in their native element under the microscope, when their graceful movements will elicit the utmost admiration. Sometimes they are suggestive of palm trees with the crown of leaves fully expanded and gently swaying in the air ; but the illusion is often quickly dispelled by the sudden closing of the fancied leaves, and the animal nature is revealed in the efforts of the polypite to secure some minute prey. When the food has passed into the stomach, the polypite expands again to its original beauty. Leaving the aesthetic side of the subject for a moment (in which there is ample scope for gratification), we will turn to the scientific and get some idea of the grade of organization which the Hydroids hold, more especially with reference to their near neighbours in the animal kingdom. Structure of Polypite. The Polypites, in the typical and fixed phase of their existence, are of very simple structure, and STRUCTURE OF POLYPITE. 5 the organs may be very briefly enumerated, viz. : a mouth, a stomach, and arms or tentacles with which to grasp their prey. Stinging apparatus. In addition, the tentacles are provided with stinging darts, by means of which the animals overcome the struggles of their victims. These darts are very intesting structures, consisting of sacks more or less oval in form, containing long, coiled-up tubes, which are shot out like harpoons and penetrate or adhere to the quarry, which may be a minute worm or crustacean. These dart sacks are formed within a single cell. Darts poisonous. All experiments and observations concerning these darts tend to show that poison is infused into the victim. Body and Stomach sack-like. The body of the polypite may be compared with a sack or bag, the tentacles being arranged around the mouth or body. Body wall consists of an inner and outer layer of Cells, with intermediate Membrane, Non-cellular. The whole body wall, including tentacles, consists of an outer layer of cells (" ectoderm ") and an 6 BRITISH HYDROID ZOOPHYTES. inner layer of cells ("endoderm"). The latter differ in character from the former, the endoderm cells being capable of throwing out and withdrawing lobular processes (" pseudo- podia "), and also others which are lash-like (" flagella "). These two layers of cells are separated by a fine membrane which differs from the middle layer (" mesoderm") of the sponges, and other groups, in being non-cellular and having no structure. It is known as the (" mesogloea "). No through alimentary Canal. From the sack-like nature of the body, it will be noted that there exists no through alimentary canal such as we find foreshadowed in the higher Coelenterates, and well-marked in the Echinoderms. The base of the body of the animal is used for attachment, or, as a surface by which to crawl. No Organs of Sight, etc. This description applies to the polypite phase only of the Hydroid career, in which stage sense organs (organs of sight, etc.) such as are found in another — the Medusa — phase are wanting, as also certain "pores" which subserve excretion. THE NATURE OF BUDDING. 7 Nerves and Muscles. As regards nervous and muscular systems. In the tentacles, branching nerve-cells are found at the base of the ectoderm cells immediately in connection with a layer of single unstriped muscle filaments which lie between the ectoderm and the fine membrane (inesogloea), and, according to Parker and Haswell, are a derivative of the ectoderm, and may be regarded as a Rudimentary Mesoderm. Colony-budding. Reference has been made to the peculiarity which specially characterises these Hydroids of forming groups or colonies, sometimes consisting of millions of creatures all in organic connection. These creatures, in common with many other of the lower animals, have the faculty of multiplying by means of budding, as it is termed. Budding distinct from ova- production. This method of reproduction is entirely distinct from that which takes place by means of ova, and may, perhaps, be tersely described as being produced by a simple inflation of the body wall (budding an inflation of body wall) ; such inflation when perfected by the formation of a mouth 8 BRITISH HYDROID ZOOPHYTES. and tentacles, constitutes a new individual. These buds, in some few species (Hydra, etc.) become detached, and like their parents, lead a solitary existence (solitary polypites), but, they also, and far more frequently, remain permanently connected with the parent growth, and by continuous budding produce branching plant-like structures. (colony budding). " Ccenosarc," or connective parts. Between the parent creature and the young bud there is generally a new piece of stem formed which serves as a connective part joining the bud to the main stem. Probably this arrangement enables the young bud the better to obtain sufficient space for its develop- ment, the expansion of the tentacles, and the procurement of food. These intermediate portions which connect the polypites, are termed the Coenosarc (meaning common flesh). Protective resemblance to seaweeds. So nearly do these growths resemble seaweeds that the majority of observers mistake them for seaweeds. This close resemblance may therefore very probably serve as a protection against their enemies which might show less SKELETAL FRAMEWORK. 9 partiality for seaweed than for animal diet, and so leave them undisturbed. Or it may have this effect — that the unwary and desir- able quarry upon which they feed can approach them without fear or misgiving. However this may be, the resemblance is so striking, that even the student may now and then be deceived. Budding, common in lower animals. The process of throwing out buds, which become detached, is common to other low forms of life besides the hydroids ; but this peculiar habit of continuous permanent budding is nowhere else carried to so high a degree, except in the nearly allied Coral polyps, * and the somewhat distant Polyzoa. The Skeleton. The polypary. Hydroid animals, being of such an extremely delicate and slender nature, demand, like most other animals, some support and protection in the form of a skeleton, either internal or external. That which the hydroids have developed, is in the form of an external *For the purpose of distinction the hydroid animal is termed a Polypite ; the coral animal a Polyp ; and the polyzoa a Polypide. Polyp meaning "many footed," and the termina- tions, ide and ite, "like." 10 BRITISH HYDROID ZOOPHYTES. tube or casing composed of a horny substance called Chitine. This casing forms a somewhat loose jacket, and clothes in the more simple forms (ATHECATA) only those stem-like and branching portions (Coenosarc) of the animal structure. In a few exceptional cases the skeleton is of carbonate of lime. These little horny branching growths are frequently cast upon the beach in tangled masses with seaweed and other objects. On examination with a lens, it will be generally found that the tubes are empty, the animal part having become decomposed. The entire horny envelope of the colony is called the polypary. Polypite receptacles. In the higher forms of hydroids (THECAPHORA) this covering is more fully developed, and is expanded so as to form receptacles for the polypites themselves. These receptacles take the form of chalices or elegant cups, often with deeply scalloped margins and ringed stems. Those with the ornamented margins bear a close resemblance to the delicate little flower, the Hare-bell, and they have consequently been named " Campanulariidae." " GUARD-POLYPITES." 11 Receptacle door, or lid. In some cases, amongst the higher kinds, there are devices for closing the top of the receptacle by a lid of various forms, which is forced open when the animal emerges, and closes when it retires. The lid is either external or internal, the latter form being the higher development. "Nematophores." Attention should also be called to certain peculiar bodies called "Nematophores" or "Guard-polypites," which are found on the stem and branches of the Pltimulariidde, and often closely associated with the polypites. They have been carefully studied by Allman, and appear to be a prolongation of the outer animal layer of the ccenosarc, and show the lobular movements peculiar to the lowest form of animal life, mz., the amoeba. (Amoeba - like character of Nemato- phore). They may be readily watched in either Plumularia or Aglaophenia. In the latter they are found exceptionally distributed over the egg-case. Their functions are not fully understood. In some instances dart sacks are found in connection with them. 12 BRITISH HYDROID ZOOPHYTES. Formation of Bud. It has already been mentioned that each member of the hydroid community is formed by what has been described as an inflation of the body wall, which consists only of an inner and an outer layer of cells, and an intermediate membrane. Hollow connection between parent and bud. This statement implies that there is a hollow connection between the alimentary cavity of the parent and the new bud, which allows the nutriment elaborated by the parent to be conveyed to the young bud for its nourishment. (Circulation of nutriment.) This step is repeated with every bud formed, so that it will be understood that a regular circulation of nutriment previously prepared in the stomach of each polypite, can be continued throughout the whole colony, and utilized by those members requiring it. Circulation maintained by " Cilia." Each individual can either pass it at will into the common channel, or can itself draw upon it. The current of this material, passing up CIRCULATION OF NUTRIMENT. 13 and down the tubes, is maintained by means of cilia — minute hair-like processes, which by constant waving keep up the circulation. Object of circulation. It may be thought that this common supply is unnecessary, that each member could find ample food for itself. But there are the immature buds ; the intermediate parts of the structure, that is, the coenosarc, with the Nematophores; and, more important than all, certain other individuals yet to be described, which in consequence of special and important duties devolving upon them, are in many cases rendered incapable of obtaining food for themselves. A brief description of these members of the colony will follow. Dispersal. It will be evident that if multiplication of the individual be restricted to the method already described, (viz., permanent budding), dispersal of the species could not take place. Nature has therefore allotted to certain individuals of the colony the duty of bearing other and special buds possessing the 14 BRITISH HYDROID ZOOPHYTES. power of reproduction by means of ova.* This order of reproduction is usually described as " Alternation of generation," and this is the earliest instance of its occurrence in the animal kingdom. It is very important to realize these steps, more especially as they are to a great extent obscured in many instances. We will therefore enumerate them thus : The "Alimentary" polypite. 1.— Ali- mentary Polypite. The ordinary colonial polypite, whose only duty is to obtain and assimilate food for itself and the colony, but which takes no part in the work of propaga- tion. The "Select" polypite. U.f— "Select" Polypite. Certain of the above, which, for reasons stated in the foot-note, we *It is extremely interesting to note the parallelism with this order in the plant world. For example: Amongst the Ferns (Cryptogams), if one of the spores found on the back of a frond be sown, the result will not be a fern, but a very small and simple plant — a leafy expansion, called a prothalium. It is the function of this little plant to produce the male and female elements ; and so soon as fertilization has taken place it dies leaving the embryos (" oo-spheres "; to develop into proper ferns. tThe "Gonoblast" idea of Huxley and the "fertile polypite" of Hincks. Some apology seems necessary for presuming to suggest a more suitable term for these Buds, in ORDER OF REPRODUCTION. 15 have called the "Select" Polypi tes, generally more or less modified or atrophied, whose special function is to produce — not eggs, but special buds of either sex, which, in the case of the females, do produce eggs. " Reproductive " bud. 2. — Repro- ductive Buds (" Gonophores "). Those special buds, whose main function is the reproduction of the species by means of ova. Modification of " Select " polypite. The important duties imposed upon the select polypites have been instrumental in more or less considerably modifying their original character as alimentary polypites ; so much so, that in many species they have lost the tentacles, and even the mouth and stomach, and have become mere stumps. (Loss of tentacles, mouth and stomach.) Under these circumstances, it will be seen how very necessary for its maintenance, and for that of the face of such authorities as the above-mentioned. These terms appear, however, to mislead, since both expressions unquestionably imply the seed or ova-bearing Buds. Now these are not the seed or ova-bearing Buds, but polypites which bear those Buds. The term " Select," or Selected, is free from this signification, and at the same . time distinguishes these Buds from the ordinary alimentary polypites. 16 BRITISH HYDROID ZOOPHYTES. its future progeny, is the common supply of nutriment which it can always obtain, and which is kept circulating through the connect- ing channels of the colony. Division of labour. We have here, in this " select " polypite a primitive example of the principle of division of labour ; all its energies, in many cases, being devoted to its special function, just as the various cells of which our bodies are composed have their particular characteristics and special duties. Specialised individuals. Among the hydroid colony the specialisation of individuals is not confined to the example previously stated. There are others whose functions are not so clearly understood (Hydractinia). Refer- ence will be made to these in the description of the specimens. Sexes of " reproductive" buds. At certain seasons of the year these "select" polypites throw out the reproductive buds. These on a given colony, may be either all male, or all female, or there may be some male and some female, but the former disposition is the more usual. THE "SWIMMING-BELL." 17 Two methods of dispersal. When these reproductive buds reach a certain stage of maturity, it will be found that two different methods of dispersal are adopted. "Reproductive" buds either fixed or free. In one case, the buds (of either sex) become detached and migrate, fertilization taking place either before or after. In the other they remain attached. The ova are set free on the spot and disperse, and are termed "planulse." "Swimming-bell." In the first case (mainly obtaining amongst the lower forms), the young bud is liberated ; it then assumes the condition known as the swimming-bell, and propels itself through the water by means of cilia, to which reference is made hereafter. The bud itself is essentially a polypite, that is to say, it possesses a typical mouth and stomach. Development of the "bell." The animal in the region of the tentacles becomes greatly expanded laterally at the expense of that portion of the body below the tentacles, and now takes a cup or saucer-like form, overhanging the free, oval end of the animal. 18 BRITISH HYDROID ZOOPHYTES. A bell with a clapper will serve as an illustra- tion. The clapper representing the polypite with the mouth at the free end, the bell corresponding exactly to 'he large expansion of the base. Sometimes there is a thin membrane partly closing the mouth of the bell called the " veil." Radiating canals. Opening out of the base of the stomach and traversing the bell radially, like the ribs of an umbrella, are four or more channels which extend to the margin of the bell and unite by running along it ; this canal system serves to convey nutriment from the stomach to parts of the bell. Channels, the homologue of ten- tacles. It has been conclusively shown that these radiating canals represent the polypital tentacles* which are formed after the same manner as the buds, viz. : by the simple process of inflation, thus producing long, tubular processes, which, in most polypites are closed, but in some are open. The bud, therefore, in progressing through the water, strongly contracts the bell, and thereby expels the water, the re-action *See Clavatella, Hincks' Brit. Hyd. Zoophytes, p. 70, et seq. SECONDARY BELL-TENTACLES. 19 carrying it backwards.* The bell then resumes its original form and the process is repeated. " Bell " and mouth tentacles armed with dart-sacks. To complete the description of the fully-developed free bud. Tentacles are sometimes formed around the mouth and also from the margin of the bell, from which they hang as long streamers, and are armed with powerful batteries of dart-sacks. Secondary tentacles. In a few species which have not the bell fully developed and therefore are not so well fitted for swimming, the bell-tentacles throw out near their ends secondary tentacles, and these they use with which to walk as on stilts. Sometimes suckers are formed at their ends. Organs for seeing. At the base of the bell-tentacles are little granular masses of pigment, generally of an orange colour, in some cases a crystalline body is embedded in * Amongst the Molluscs, the Cuttle fish and others of its kind, progress after the same manner, and in a backward direction, by the sudden expulsion of water from a kind of pouch. Some bivalves, also, propel themselves by suddenly closing their valves and expelling the water. 20 BRITISH HYDROID ZOOPHYTES. them. To these organs the power of sight is attributed. In addition, along the margin of the bell there occur other organs which have more the appearance of eyes, very prominent and staring in character. Lithocysts, organs of direction. These are little globular sacks containing a calcareous spherule, and are termed lithocysts. It was formerly thought that they might have been organs of hearing, but they are now regarded as organs of the sense of direction, in steering a course. Nerves and Muscles. With regard to the nervous and muscular systems entailed by the development of the " bell " for swimming purposes. Romanes, in his work on u Jelly Fish, Starfish and Sea Urchins," gives an interesting account of experiments in dissection which he carried out on the Hydromedusae, pointing conclusively to a differentiation of tissue in the direction of nerves and muscles. Two rings of nerves. It is now, however, established, that there exists around the margin of the bell, two rings of nerves and nerve cells, one ring occurring just above and the other just below the " veil " process. EXCRETORY ORGANS. 21 Primordial centralized nervous system. These rings afford the earliest example of a central nervous system in the animal world. As to muscles, the whole inner surface of the bell is lined by fine cancellated muscular fibres. Muscular tissue also occurs in the "veil." Primordial specialised excretory organs. In some species of these medusoid free buds, " pores " occur leading out of the marginal canal. These pores subserve excre- tion of whole matter and mark the earliest occurrence of special organs for this purpose amongst animals. In this free bud, which we have cursorily described, with its " bell :> and trailing tentacles, we are introduced to particular forms of creatures, which are well- known as Jelly-fish, but whose life-history is not so fully understood.* *A distinction must, however, be made between the naked-eyed and covered-eyed Jelly-fish ; the hydroid offspring corresponding to the former only, the latter being the offspring of the higher hydrozoans. 22 BRITISH HYDROID ZOOPHYTES. Jelly-fish hatches her eggs, then called "planulse." The freed bud, or jelly-fish, after seeing something of the world of waters around it, may, in the ease of a female, settle down, attach itself to some object, and ultimately give birth to a family, the members of which sooner or later disperse. They do not, however, in this, the larval stage, resemble either the polypite or their immediate parent the jelly-fish, but are little, flat, conical bodies called planulre, which, in their later stages, enclose a cavity and swim by means of cilia. "Planula" is modified into a polypite. Later on they attach themselves to some object by their larger end, which expands and divides into root-like filaments. A mouth and tentacles are formed at the upper end and the result is a polypite, similar to that which originated the colony. These polypites will then proceed to carry out the principle of continuous budding, and thereby form fresh colonies. First method of dispersal. '* Repro- ductive " bud bodily transported. This is one method by which the ova are METHODS OF DISPERSAL. 23 transported, viz. : by the mother-bud freeing herself from the colony and bearing the brood away to another place, and thus establishing a new centre of distribution. Second method. Bud remains attached, ova set free. The reproductive buds in this case remain attached to the parent, fertilization takes place, and the ova (planulae) are set free, disperse, and go through the same modifications as the planules of the detached buds, preparatory to establishing fresh colonies in the same manner. "Select" and "Reproductive" buds nearly obliterated. The buds styled " select " and " reproductive," demand some further remarks. In many cases, their real identity as originating in distinct buds is almost wholly lost, and it is difficult to recog- nize any trace of bud unless it is known that a solution of the difficulty is to be found in certain links or intermediate forms. We will, therefore, set those interested in such matters at once on their guard. Hincks calls attention to these gradations, and his work on the Hydroids should be consulted by all who desire to study this group of animals. '24 BRITISH HYDROID ZOOPHYTES. Modification and atrophy of "select" bud. Beginning with the " select " polypite, that is to say, with the individual which displays the first step in the series of phenomena connected with reproduction. In the lower division (ATHECATA or naked polypites) some members which bear the gonophores are not modified at all, but in many species the tentacles become more or less aborted and the polypite stunted, and when the higher division (THECAPHORA or sheathed polypites) is reached the " select " polypites do not obtain nourishment from external sources, in fact, they have no mouths and are wholly unrecognizable as polypites. There is, however, one exception in this division, amongst our British species, and that exception is the Genus HALECIUM, Oken, where the " select " polypites are fully developed, in other cases they are represented by a mere stump ("Blastostyle") bearing the reproductive buds In THECAPHORA, that which repre- sents the "select" polypite is provided with a receptacle, fairly strong and modified to the special circumstances of the case. This modi- fied receptacle is more in the nature of a case ATROPHY OF BUDS. 25 or vessel because it contains not only the aborted " select " polypite, but also the repro- ductive buds bearing the ova. It is therefore termed a " capsule." Modification and atrophy of 4 * Reproductive" bud. In the ATHECATA and simpler THECAPHORES, the " reproductive " bud is generally a Medusa, but in some species of ATHECATA the bud remains attached. In the THECAPHORA, however, we soon reach a certain point— the turning point — where, as in such cases as Gonothyrsea Loveni, Allman, liberation fails to take place and thenceforward \\\vfixed bud is the distinguish- ing feature. The bud having now become a fixture, loses its individuality and the bell and tentacles dwindle away and the creature wastes down to a mere sack, which contains in its walls the ova. The bud, in both ATHECATA and THECAPHORA, is nearly always enclosed in a fine envelope, which eventually ruptures. We have seen, therefore, in the final stages, the " Select" bud and the "repro- ductive" bud, both becoming obsolete, and almost all that remains ostensibly in their place, are the ova within the Capsule. Under 26 BRITISH HYDKOID ZOOPHYTES. these circumstances, it is difficult to discriminate between these two buds, and it will therefore be convenient when this is the case, to suppress their individuality and to refer to the whole body as the egg-capsule, or simply, the capsule. Where, however, the " select " polypite is recognizable, as in ATHECATA,and is distinct from the reproductive bud, the latter with its envelope is also called the " gonophore." Process of Budding, and Budding of Medusae. The process of budding, as previously stated, is by inflations of the body wall, which is composed of an inner and an outer layer. This process takes place not only in the polypites, but also in the Medusae, in which latter case the buds are Medusae. Ovaries are situated in body wall, also in radiating canals of Medusae. Ova are formed between the outer and inner layers of the alimentary cavity. This is the case also in the Medusae, but with some of these ova also occur in sacks (inflations of the layers) in the canals which radiate from the stomach cavity. The important distinction between budding and ova-production should therefore be clearly understood. COMPARISON WITH SPONGES. 27 Larva is a "planule," a polypite, an Amoeba, or a Medusa. Hincks states that in nearly all species the ova develop into planules, and thence become modified into polypites ; but in the fresh water Hydra and a few other species, the ova at once take the form of polypites. One instance he cites in which the egg gives place to an amoeboid form.j There are some cases also, where the ovum of the hydroid-medusa does not revert to the fixed hydroid state but is hatched out a Medusa. Hydroids compared with the sponges. Having briefly considered the nature of the Hydroids, a few remarks may not be out of place to state in what respect they differ from their neighbours on either side. The group of organisms immediately below the Hydroids, is the Sponges. They are a peculiar and somewhat anomalous group of animals. It is difficult to define their actual affinities.. Suppose, however, we take a densely- branching hydroid, such as Eudendrium, rameum, Pallas and deprive the animal colony 28 BRITISH HYDROID ZOOPHYTES. of the horny covering, and also of the polypites, leaving only the stem and branches, i.e., a system of tubes or channels (coenosarc), with their ends open. Let there now be developed between the inner and outer layer (of which the coenosarc, like the polypite, is composed) a middle and a much thicker layer of simple flesh substance called protoplasm, containing, however, numerous " flesh particles" or cells. If we then picture the cilia through- out this canal system maintaining by their movements a constant circulation, not of partly assimilated nutriment as in the hydroid colony, but water containing food which is supplied it to all parts of the system ; and furthermore, that the larger end of the main channel or central stem, into which all other channels eventually lead, be open forming an exit for the impoverished water, we shall gain an approximate idea of the comparative systems of a hydroid colony and a simple sponge. As we go higher in the sponges, instead of the channel being lined with cilia and exercising stomachic functions, the cilia become restricted to little chambers lined by cells of peculiar form (collar cells), where also COMPARISON WITH CORAL POLYPS. 29 probably food assimilation is localized, thus suggesting a comparison with the stomach of the polypite. To complete the sponge simile. Instead of the horny tubing suited to the hydroid form, there is an intricate network of horny fibres, serving as a skeleton to support the otherwise somewhat flaccid body-substance, and in addition, the structure is rendered more solid by the secretion of minute needles of carbonate of lime or flint, in the flesh and fibre. These needles may be the homologue of the calcareous skeleton of some hydroids, e.g., a foreign species of HYDRACTINIA and the fossil Parkeria and others. Hydroids compared with the Sea- anemones and the coral polyps. Higher in the scale of development, above the Hydrozoa, are placed the Sea-anemones and the Coral polyps. In the hydroid animals the stomach is a simple sack, but in the anemones and coral polyps a slight though important transformation has taken place. It is first indicated in the higher medusae. Instead of the simple sack-like stomach, the mouth portion is turned inwards, (e.g. A certain kind 30 BRITISH HYDROID ZOOPHYTES. of non-spilling inkstand). The preparation of food is carried on by this portion. The interior is called the body cavity, as distinct from the stomach. Arising out of the body wall and directed towards the pendant stomach or centre of the animal, are certain little vertical fleshy plates (Mesenteries). The anemones do not possess these modifications, but the coral polyps do, and in addition secrete carbonate of lime, or horny coral, in the deposition of which the mesenteries take part, by secreting what are known as the " septa," or rays of the coral. Hydroids and Polyzoa compared. There is so much outward similarity between these hydroid-zoophytes and certain other creatures of much higher standing, viz., the Polyzoa and Bryozoa (Molluscoida) that it may be desirable to point out the wide gap which separates these two groups. In appearance, they have much in com- mon. They are very minute ; they have the habit of permanent budding (thereby produc- ing plant-like growths) ; they secrete a poly- pary-like covering ; the animals themselves are transparent, and have a circle of tentacles COMPARISON WITH POLYZOA. 31 arranged round the mouth. On examination under the microscope, however, a considerable advance upon the structure of the hydroid will be observed. There is a well-formed through alimentary canal, entirely cut off from the body cavity, there is also a gizzard, and well-defined, though simple, muscular and nervous systems. The polypary, as it may be called, partakes to some extent, of a horny substance, but carbonate of lime also enters largely into the composition, more especially in the higher forms. The receptacle also, or cell of the polyzoan is more a part of the animal than is the case in the hydroids, where the whole polypary hangs like a loose-fitting garment on the compound animal, the former condition resembling more the relation of the shell to the shell-fish in the ordinary mollusc, to which the polyzoan is nearly allied. 32 BRITISH HYDROID ZOOPHYTES. TABLE C. Systematic Table to show the position of the HYDKOMEDUSJ3 (CEASPEDOTA) (HYDROIDS, HYDROZOA, and HYDROIDA, of various Authors) in the classification of the CCELENTERATA. PHYLUM CCELENTERATA. Radially symmetrical animals with only one cavity in the body — the gastrovascular space— which serves alike for digestion and circulation. The generative cells are always either ectodermal or endodermal. Sub-phylum I. CNIDAEIA. Ccelenterata with thread-cells. CLASS I. HFDROMEDUSJE (CRASPEDOTA). Cnidaria in which the medusa has a velum and the polyp is without gastral ridges or filaments. Order 1. HYDRIDA. Solitary polyps without medusoid buds. Both generative products are developed in the ectoderm of the polyp. Order 2. HYDROCORALLINJE. Colonial Hydromedusae, consisting of a meshwork of ccenosarcal canals, the ectoderm of which secretes a hard calcareous matter, filing up the spaces of the meshwork. Polyps of two forms, gastrozooids and dactylozooids. 2 Families. Order 3. TUBULARIJE (GYMNOBLASTEA). Without hydothecae and gonangia. Polyps, \vhen more than one, forming permanent colonies. Generative individuals, when set free, are Anthomedusae. 4 Sections. 14 Families. ANTHOMKDUS^B;. The Medusa of this Order. Craspedota without otocysts. with ocelli at the base of the tentacles, and with manubrial gonads ; radial canals, usually 4, rarely 6 or 8 ; budded from polyps of the Tubulariae. 4 Families. 13 Sub-families. TABLE OF CCELEXTERATA 33 Order 4. CAMPANULARI^ (CALYPTOBLAHTEA). With hydrothecse and gonangia. Colonial. Generative in- dividuals, when set free, are Leptomedusse, 4 Sections. 7 Families. E. The Medusae of this Order. Craspedota partly with, partly without otocysts ; ocelli present or absent, gonads on radial canals ; budded from polyps of the Campanularise. 4 Families. 13 Sub-families. Order 5. TRACHOMEDUSu-E. Hydromedusa? without hydrosome (polyp stage) ; with mar- ginal sense-tentacles in pits or vesicles, with endodemial otoliths. Ocelli usually absent. Gonads radial. Radial canals, 4, 6, or 8, often with centri-petal canals. With thread-cell thickening of ectoderm round the edge of the umbrella. 4 Families. 8 Sub-families. Order 6. NARCOMEDUS^E. Craspedota with free auditory tentacles. Tentacles inserted dorsally on the ex-umbrella, and connected with its edge by peroniums. Radial canals, when piesent, in the form of flat, radial, gastric pouches. 4 Families. Order 7. SIPHONOPHORA. Free-swimming polymorphic colonies of Hydroniednste, pro- duced by budding from an original, probably medusoid, individual. Gonads in gonophores, which, as a rule, are not set free. Arranged by & & (After SEDGWICK). PART ii. AN ACCOUNT OF THE BRITISH HYDROID ZOOPHYTES IN THE Hastings and St. Leonards Museum* PHRT II. AN ACCOUNT OF THE BRITISH HYDROID ZOOPHYTES IN THE Hastings and St. Leonards Museum* The specimens were collected at HASTINGS by Philip James Eufford. (The following classification is after Hincks). Sub-kingdom— CCELENTERATA. Class — HYDROZOA. Order I. — HYDROIDA. Sub-order I. — ATHECATA (CORYNIDA). Polypites naked — not provided with horny receptacles. Family.— CLAVID^. Clava multicornis, Forstai. 1 specimen in liquid. SPECIMEN The Polypite is club- or spindle- 1. shaped, with the tentacles distributed over the body, the mouth being protruded conically. The gonophores are borne in clusters below the tentacles. This Hydroid is found creeping over stones, shells and seaweed, near low water, somewhat as Ivy trails over a wall ; the adherent, creeping 36 BRITISH HYDROID ZOOPHYTES. stem throwing up, here and there, erect, slightly pink, and short polypites. The polypary rises only just above the creeping base. It is not common locally. -.me/ Fig. 4. STRUCTURE OF TYPICAL HYDROID. 37 EXPLANATION OF FIG. 4. The Structure of a typical Hydroid (Hydra), and the distinctive difference between Budding and Ova production ; also a dart cell. (From Parker and Haswell^ after Schneider}. A. m. Mouth. end. Endoderm cell with pseudopodium. end9 Endoderm cell with flagella. msgl. Mesoglsea, intermediate membrane. eat. Ectoderm dt. Large dart cells. dt' Small dart cells. bd. Bud. or). Ovum. sp. Spermarium. B. tr. l ' Trigger-hair. " dt. s. Dart sack. thd. Thread coiled within the sack. dt. c. Dart cell. nu. Nucleus. 38 BRITISH HYDROID ZOOPHYTES. Fig. 5 — Hydra vulgar is, A solitary polypite. (a). — Young bud, or "inflation" of body wall. Tentacles not yet formed. (b).-— More mature bud, with tentacles, (c).— Dart, HYDRACTINIA ECHINATA. 39 Family.— HYDKACTINIHLE. HydracMnia echinata, Fleming. (Fig. 7). 1 specimen dry and 1 in liquid. SPECIMENS This Hydroid is peculiar on 2, 3. account of the form of the chitinous skeleton, and of the diversity of the members composing the colony. It is found at low or in deep water, encrusting whelk and other univalve shells inhabited by the common Hermit crab. According to Hincks, it is always found under these conditions, but we have found it on one occasion, on the claws of a large Lobster. The ordinary alimentary polypi te is white or pink, and in form very like the last species, but the tentacles are arranged in a single circle. In the " select " polypites, the tentacles are reduced almost to nil, but the remnants are well provided with dart sacks. The gonophores are collected together on the body, and are generally pink in colour. Besides these members, there are others similar in form, but much longer, and which have the habit of coiling themselves up, but they do not bear gonophores. They are 40 BRITISH HYDKO1D ZOOPHYTES. mainly found around the mouth of the shell and are the " snake- like appendages " of Hincks. There is yet another modification. Certain long, linear, worm-like bodies, very contractile, with no tentacles or mouth, but well provided with dart sacks, whose function appears to have relation to either the special protec- tion of the colony, or to be Fig. 6 — Diagram to show the nature of "Budding." (a).— Mature polypite. (b). — Young bud, or "inflation" of the endodenn and ectoderm of parent— niouth and tentacles yet to be formed. (c). — Ccenosarc, or connective parts. instrumental in pro- curing food for it. They are not generally distributed, but are found massed together. In some cases (if not in all) the walls of these attenuated worm-like bodies contain dart sacks. The heads appear to have a bi-lateral form. It is possible, as Hincks has pointed HYDRACTINIA ECHINATA. 41 out, that these, and the " snake-like " bodies may have analogy with the nematophores found in the PLUMULARIID^E, or to certain organs in Ophiodes. The nature of the chitinous crust is not very clear. The plan, however, appears to be a system of horizontal horny tubes more or less irregular, compressed closely against one another, and opening into each other, thus forming a sheet which covers the surface of the whelk shell. The exposed surface of the tubes, or crust, is perforated similarly to perforated zinc, and allows the coenosarc which fills up the interior of the tubes, also to overspread the outer surface of the crust. From this surface layer of ccenosarc the naked polypites emanate. This species is named Echinata, from the spiny character of the crust, the spines evidently serving to protect the polypites from friction against objects in the many close corners into which the Hermit crab takes them. Beneath these spines, or pinnacles, the polypites crouch and remain unharmed. 42 BRITISH HYDROID ZOOPHYTES. As to the advantages to be derived from an association of crab and polypites, the latter, doubtless, partake of the crumbs that fall from the rich man's table, and also feed a Fig. 7 — Hydractinia, echinata, Fleming. Enlarged. (a). — Alimentary polypite. (b).— "Select" polypite bearing the "Reproductive" buds containing ova. (c). — Worm-like body ("tentacular filaments," Hincks), sometimes called dactylozooid. (d). — Enlargement of head of the same. (e).— Horny spine of "crust." HYDRACTINIA ECHINATA. 43 upon small creatures such as Infusoria, which may be attracted thereto. The possible benefit derived by the crab may be found in the protection afforded against enemies (Fish, etc.), by reason of the poison darts of the polypites, but the polypites reap the main advantage, since they are, almost without exception, found associated with the crab, whereas the latter is more often found not accompanied by them. This is a particularly interesting species, and the horny skeleton should be examined with a microscope, in connection with that of Coppinia arcta, Antennularia ramosa, and several other species. H. echinata is common along our shores in warm weather, but the crab with its commensal retires to deeper water when the temperature is low. When thickly covered with gonophores, the whole colony is a pink colour, and very noticeable. 44 BRITISH HYDROID ZOOPHYTES. Family.— CORYNID^E. Coryne vaginata, Hincks. (Fig. 8 & PLATE II.) 2 specimens in liquid. SPECIMENS The polypite of Coryne, like that 4, 5. of the foregoing species, is club- Fig. 8— A Goliath (Cyclops) (a).— Slain by the darts of Coryne vaginata, in various stages of penetration. (b).— A dart much enlarged. PLATE II. 1. 2. 3, E. C. Photo, ad-nat. 1. Tulmlaria coronata. Abiidgard. 2. Coryne vaginata. Hincks. 3. Obelia gelatinosa. Pallas. nparlv nat. EUDENDRIUM RAMOSUM. 45 shaped. The tentacles are distributed over the body, but they differ in having the ends knobbed, the knobs being fully armed with dart sacks. The gonophores are round or oval in shape, and are formed between the tentacles. The main stem is erect, and rises to a height of four or five inches. It branches at intervals and becomes several times pinnate, the polypites being terminal. The polypary is regularly ringed, and extends to the base of the polypite, where it slightly expands and is more or less wrinkled. Coryne vaginata is common in rock pools from mid to low tide. Family. — EUDENDKIID JE Eudendrium ramosum, Linnams. (PLATE III.) 2 dry specimens. SPECIMENS Polypites pink with many 6, 7. tentacles in a single circlet. Stem long and alternately branching. Polypites terminal. The polypary is of a dark to light brown colour, extending to the base of the polypite but does not then expand. 46 BRITISH HYDROID ZOOPHYTES. Fig. 9 — A Hydroid. Branches are annulated in the lower parts. This zoophyte is long and slender and of a switch- like character. It is trawled in shallow or deep water, and is rather common. Eudendrium rameum, Pallas. 2 dry specimens, 2 specimens in liquid. SPECIMENS This species 8, 9, 1O, 11. has been aptly compared with an old weather-beaten tree. The main stem and branches are thick and strong, being formed of many tul es adherent to- gether. The terminal shoots consist of single tubes which are short. The polypary is slightly ringed in (a). — The receptacle of which is furnished with a door or lid. (b). — Receptacle en- rg(c).— Lid or 'opercuium.' places ; the gonophores PLATE III. HR E. C. Photo, ad nat. Eudendrium ramosum. Lmn*us. (Nearly nat. size.) PERIGONIUMS REPENS. 47 are borne in bunches, like grapes, on polypite or coenosarc ; they are plentifully distributed over the specimens preserved in liquid. Family.— ATRACTYLID^. Perigoniums repens, Wright. Specimen on shell, in liquid. SPECIMEN The polypite is club-shaped with a 12. single circlet of tentacles, and arises by a stem from the creeping root-like ecenosarc. The polypary is of a reddish brown colour and extends to the base of the tentacles, where it expands into a cup-like receptacle, not, however, of such a finished character nor capable of covering the whole polypite as in the sub-order THECAPHORA. The gonophores are formed on the stem, the reproductive bud being a free medusa. The species is rare at Hastings. It was trawled on Nucula nucleus together with Lovenella clausa, another rare species, on the same shell. 48 BRITISH HYDROID ZOOPHYTES. Garveia nutans, Wright. 3 specimens in liquid. SPECIMENS The Hastings specimens are 13, 14, 15. found creeping up the stems and branches of other hydroids, such as Hydrallmania, throwing up simple stems with polypites and ccenosarc of a carrot pink colour, which readily catch the eye. The polypites are club-shaped. The tentacles number about twelve, and are in a single circle. The polypary is transparent and faintly ringed, and is expanded trumpet-wise, conformably with the polypites. The gono- phores are round or oval, of an orange colour, and emerge from a slightly expanded polypary. The specimens were trawled off-shore, also from deeper water, and are somewhat rare. There are slight differences between the Hastings specimens, and those described and figured by Hincks, not, however, sufficient to warrant a fresh specific description, the main point of difference being, that in the present examples they are parasitic, and consequently do not require to form a strong compound stem. PLATE IV. E. C. Photo, ad nat. Ttilularia indivisa. Linmeus. (Nearly nat. size). TUBULARIA INDIVISA. 49 Family.— TUBULARIID^E. Tubularia indimsa, Linnseus. (PLATE IV.) 1 dry specimen and 1 specimen in liquid. SPECIMENS The polypite of Tubularia indimsa 16, 17. is ovate in form, and reddish in colour. There are two separate rings of tentacles, one around the mouth, and the other at about the middle of the polypite. The gonophores are formed at the foot of the body- tentacles in stalked clusters. The polypary is neither branched nor ringed, and extends upwards to the base of the polypite. In these Tubularians the need of a support for the polypites suggests itself very forcibly ; the body seems top-heavy and liable to break otf when swaying with the movement of the water. This species is common in shallow or deep water off Hastings, but grows much finer in the latter situation. It requires to be preserved immediately on being taken. Tubularia coronata, Abiidgard. (Fig. 10 and PLATE II.) 1 specimen in liquid, also Medusoids in liquid. SPECIMENS This species appears to be a rare 18, 19. visitant to Hastings, and will, therefore, receive more notice here than would O •£ r^ TUBULARIA CORONATA. 51 otherwise have been the case. The zoophyte in Hastings specimens is from an inch to an inch-and-a-half high and branches very little. The polypary is transparent, white, or flesh- colour. The general colour of the polypites is orange-red, but this, on close examination, may be observed to be confined mainly to the proboscis and gonophores. The polypites are similar in shape to those of the last species. The mouth is surrounded by a ring of about twelve tentacles, and around the body, near the base, is another circle of transparent tentacles considerably longer than those around the mouth, and numbering about twenty-five. Just within this circle of tentacles the gonophores are situated ; they are oval and borne on short stalks, and are generally of an orange-red colour. The reproductive bud, on liberation, is medusa-form, but without the bell, and of an elongated egg shape, with a slight constriction towards the basal or larger end. At the narrower end, where the mouth is situated, there are four short and thick tentacles which are very similar in size and appearance to the tubercles which are 52 BRITISH HYDROID ZOOPHYTES. noticeable at the apex of the gonophores before liberation. About midway down the body, there is a ring of much longer tentacles, clubbed at their ends. This feature appears to be an important specific character. These long tentacles number from about nine to twelve, each alternate one being raised, and the others lowered, with a slow finger-like motion. On liberation, these little creatures appear rather sluggish in action and ill-adapted for locomotion, since they have no bell, nor are the tentacles specially suited for walking. It appears to be a matter of indifference to them whether they rest upon the base of the body, or on the tentacles. Hincks states that they can use the tentacles as oars. This method of progression was not noticed in the Hastings specimens, although these buds were given off in a glass vessel without persuasion. T. coronata appeared along the Hastings coast in the latter half of the year 1897, in great profusion, and was found from about half tide to low tide. Towards the end of the year, rough weather set in, and destroyed all the colonies, which, however, by this time, CLYTIA JOHNSTON!. 53 had mostly shed their reproductive buds. Neither before, nor since this period, has this species been recorded for Hastings. It came in great profusion, and vanished suddenly, and completely. Possibly some unusual set of the sea-currents may have brought the embryos to this shore. The specimen in the preservative bears the gonophores, and the free reproductive buds will be found separately in a tube. Sub-order II. — THECAPHORA. Poly piles provided with cup-like receptacle of the Polypary. Family— CAMPANULARIID^E. Clytia Johnstoni, Aider. (Fig. 11). 2 specimens in liquid. SPECIMENS With this species is introduced 2O, 21. those hydroids in which the polypary is extended, and expanded into a finely formed cup, so as to provide protection and support to the polypite. In Clytia Johnstoni, the unbranched stems rise from the creeping base bearing at the ends beautiful Fig. 11 — A typical Hydriod Clytia Johmtoni, with its free Reproductive bud, or Medusa, (Enlarged.) CLYTIA JOHNSTON I. 55 cup-like receptacles with toothed rims, in which the polypite is comfortably ensconced, and where it can expand or withdraw at will, In the ATHECATA, two species (Perigoni- mus repens and Garveia nutans) have been mentioned in which a rough expansion of the polypary takes place, but there is a great difference between those species and the beau- tifully finished chalices of the THECAPHORA, of which C. Johnstoni forms a good example. The stems are ringed or wrinkled at the top and bottom, and occasionally in the middle. The polypite has a single circle of tentacles. The gonophores are borne on the creeping (A). — " Alimentary" polypite, tentacles retracted. (B). — " Select " polypite and modified receptacle, the repro- ductive buds being produced within the darkly shaded enclosure which represents the " Select" polypite. (C).— The freed reproductive bud, or jelly fish, seen rather from below. (a). — Stomach, or polypite, with the mouth at the free end. (b). — One of the radiating canals, with reproductive sack. (c). — Bell tentacles. (d). — Organ of sight, Ocellus. (e).— Lithocyst. (v). — Veil, a thin membrane partly enclosing bell-cavity. 56 BRITISH HYDROID ZOOPHYTES. base, or occasionally on the stem, the horny receptacles or capsules of these being ringed or wrinkled. The reproductive bud is a free medusa with four canals radiating from the stomach to a canal around the margin of the bell. At each of these four points, there is given off a tentacle. Midway between these are swellings representative of other and rudimentary tentacles. On either side of these the eye-like lithocysts occur. The bell is a very beautiful object ; transparent and finely spangled with opaque white dots. The mouth of the bell is partly closed by a fine membrane, the veil. Obelia geniculata, 1 specimen in liquid. SPECIMEN The genus OBELIA differs from the 22. genus CLYTIA mainly as regards the reproductive bud, which, as in the previous specimen, is a medusa, but the bell in OBELIA is almost flat or saucer shaped, and the tentacles around the bell are far more numerous. The creature has a peculiar habit of swimming sometimes with the mouth OBELIA GKLATINOSA. 57 uppermost, and the bell turned inside out. When in that condition, it is highly suggestive of an umbrella in a like predicament. The specific name is very appropriate, signifying bent like the knee. It may be called the zig-zag hydroid, a term which equally well describes it. The hydroid throws up zig-zag stems, and from each bend rises a short ringed shoot bearing a polypite, the receptacle of which is somewhat triangular with a plain rim. The capsules which are large, and urn- shaped, are borne in the axils of the shoots. This species is very common and overruns many objects. Obelia gelatitiosa, Pallas. (PLATE II.) 1 specimen in liquid. SPECIMEN This is one of the tallest and most 23. conspicuous of the shore* hydroids. The stem is compound, some five or six inches in height, with branches arranged in whorls around the axis ; these, again, throw out secondary shoots. The polypary is ringed just above the branching, and the receptacles * i.e. Growing on rocks, stones, &c., between tide-marks, 58 BRITISH HYDROID ZOOPHYTES* are somewhat deep, the rim of which, accord- ing to Hincks, is castellated, or squarely toothed. This character we have not observed in the Hastings specimens, although they must, undoubtedly, be referred to the same species. The capsules are borne in the axils of the branches and are about twice the size of the polypite receptacle. This hydroid is found plentifully on stones and rocks near low water, very often in flat, exposed situations, and apparently it does not object to muddy surroundings. Obelia longissima, Pallas. 1 specimen dry. SPECIMEN This species is tall, delicate, and 24. attenuated in mode of growth. The specimen when living, measured about twelve inches in height. The main stem is simple, with branches thrown out alternately around the axis, at which points, the stem bends slightly outwards, the polypary being ringed above the branching. The rim of the receptacle is squarely toothed as in the last species. The capsule is wider and not so elongated. OBELIA DICHOTOMA 59 This species is common in deep water, and may be found amongst the trawlers' rubbish, where it has much the appearance of tangled horse-hair. Obelia dichotoma, Linnaeus. 1 specimen in liquid. SPECIMEN This specimen is apparently Obelia 25. dichotoma. It bears a great resemblance in details to 0. gelatinosa, and U. longissima, but differs from O. gelatinosa in habit, and in the stem being simple instead of compound ; from 0. longissima in form, habit, etc. ; and from both because the rim of the receptacle is not toothed. The specimen is on a fragment of Tubular ia. Not very common. Campanularia verticillata, 1 specimen dry, 1 in liquid. SPECIMENS This is a very distinctive species. 26, 26a. The stem is compound and throws out around its axis branches which branch again. The polypites are borne on rather 60 BRITISH HYDROID ZOOPHYTES. long straight shoots, more or less distinctly ringed, and the rim of the receptacles is indented. The capsules are somewhat oval, with the upper part gradually drawn out to a narrow neck. They are formed on the stem and branches generally. This has been called the Horse-tail hydroid, since it bears some resemblance to the plant Equisetum. It is not uncommon in the trawl from deep water, but is not a shore species. Lovenella clausa, Loven. On specimen number 12. SPECIMEN This is a beautiful and apparently 27. rare species. It throws up from a creeping base, simple, generally unbranched, stems, more or less ringed or wavy, with terminal polypites. The receptacles are deep and taper gradually downwards, the thickness of the chitine being greater towards the base. The rim of the receptacle is scalloped, producing slight angularity at each crenation. The special peculiarity of this species is, that when the polypite retires into the receptacle, pointed OPERCULARELLA LACERATA. 61 prolongations of the receptacle are directed to a central point, and, closing over the polypite, form a conical roof. Capsules not present. Rare. (See Fig. 9.) Opercularella lacerata, Johnston. 1 specimen in liquid, on a Polyzoan. SPECIMEN An extremely delicate species, and 28. one very readily overlooked. In the present specimen, it is found running up the stem and branches of a polyzoan, Anguinella palmata, Van Beneden, from which, with great care, it could be removed. It gives off ringed undulatory stems with short ringed side shoots, bearing ovate receptacles. These are produced beyond the rim, with points, which meet conically over the aperture, forming a lid. The polypite is long and linear, and when expanded extends fully the length of the receptacle beyond it. The mouth is slightly conical, and the tentacles are long and number about sixteen. Capsules not present. This species bears a very close resem- blance, in many respects, to Calycella syringa, Linn. Found near low water. 62 BRITISH HYDROID ZOOPHYTES. Family— LAFOEID^E. La/oea dumosa, Fleming. 1 dry specimen, 1 specimen in box. SPECIMENS This hydroid is found either 29, 3O. twining up some other species or over running other objects, and in this, the creeping condition, the stem is simple (single). In another phase, the stem is erect and branching, in which case it is compound, as are also the branches. This habit of producing a compound stem is apparently induced by the need of stiffening and support for the zoophyte. The receptacles are tubular and somewhat curved. There is a short pedicel, and in the upright form the receptacles are arranged around the axis. Capsules not present. This species is common in deep water. Two other species, L. podttum and L parvula, Hmcks, have been found locally. Filellum serpens, Hassan, 1 specimen. SPECIMEN The character of this species is 31. similar to that of the last, but the stem is creeping and reticulate, and is set in a COPPINIA ARCTA. 63 horny crnst The receptacles are curved, bearing some resemblance in shape to the old-fashioned powder horn. The lower half of the receptacle is adherent to the crust. F. serpens is very common on the stems of other hydroids, rarely on shells. Family— COPPINIID^E. Coppinia arcta, Daiyeii. (Fio, 12.) 1 dry specimen in box. SPECIMEN The receptacles are long, tubular, 32. and curved, and are set in a horny cellular crust which invests the tubes of other hydroids. A comparison of sections of this crust with that of Hydr actinia, and the stem of Antennularia ramosa, and others, will be found instructive. Common in the coralline zone. Family— HALECIID^E. Halecium halecinum, Linnaeus. 1 specimen dry, of exceptionally fine growth. SPECIMEN This has been called the herring- 33. bone hydroid, because the stem and main branches, which are compound, throw out regular, alternate, lateral branches. Fig. 12 — Transverse section of polypary of Coppinia arcta for correlation with crust of Hydractinia (Fig. 7), and tho section of stem of Antennularia (Fig. 13). (a). — Zoophyte stem, upon which Coppinia arcta is parasitic. (b). — Horizontal cells or tubes (?), from which arise the vertical tubes c. (c).— Vertical polypite tubes. HALECIUM HALECINUM. 65 The receptacle is tubular and telescopic in appearance. The male and female capsules differ in shape. Hincks* draws attention to the fact (it is well worth personal observation) that in the case of the female capsules of this genus, they are surmounted by two fully developed " select " polypi tes ; and he cites this as the only case among the THECAPHOEA in which these are not entirely suppressed. This fact should be carefully noted. In this species the mouth of the capsule projects beyond the ovary. Common in the trawl, more especially in rather deep water, but is not of particularly fine growth. (d).— Thick floor of chitine. (e). — Appearance of tubes on surface. In the horizontal cell or tube from which the left hand vertical tube arises, are seen two dots, which probably represent openings in connection with other tubes or cells. The system is practically the same as in Hydractinia and Antennularia ramosa, and others. * A History of the British Hydroid Zoophytes. Vol. I. p. 221. 66 BRITISH HYDHOID ZOOPHYTES. Halecium Beanii, Johnston. 1 specimen dry. SPECIMEN Halecium Beanii may be known 34. from the last species by its very delicate character, and instead of the straight, rigid appearance, the tender branches are rather zig-zag, giving off the shoots at the angles. The " select " polypites are fully developed, as in H. kalecinum, but the region of the capsule where the eggs are located, protrudes beyond the mouth of the capsule. This, however, is not so in the other species. Family— SERTULARIID^. Sertularella polyzonias, Linnaeus. 3 dry specimens, and 1 specimen in box. SPECIMENS This family exemplifies 35, 36, 37, 38. those hydroids in which the receptacles are unstalked and arranged on opposite sides of the axis. This is a lowly and straggling form, the stem not being appreciably stronger or thicker than the branches. It overruns many objects, especi- ally Flustra (a Polyzoon). The receptacles SERTULARELLA GAYI. 67 are alternate, giving a slightly zig-zag appearance to the growth, and are not wrinkled as in S. rugosa. The capsules are ovate, wrinkled, aud have a slight neck to the aperture. Very common. Sertularella Gayi, Lamouronx. 2 dry specimens. SPECIMENS This species bears much 89, 4O. resemblance to the last, but has a compound stem, and consequently, a much stiffer appearance. The receptacles are slightly wrinkled and are alternate. The capsules are somewhat spindle-shaped, and are only wrinkled in the upper part. Less common than S. polyzonias, and from the trawl only. Sertularella rugosa, 1 specimen in box. SPECIMEN This might be truly called the 41.. wrinkled Sertularella. The speci- men exhibited has overrun a piece of Flustra (a Polyzoon), throwing up here and there 68 BRITISH HYDROID ZOOPHYTES. small shoots, densely crowded with ovate, alternate receptacles ; features in which, as also in the marked wrinkling, they much resemble the capsules, which, however, are very much larger. Common. Sertularella tenella, Aider. 1 specimen in box on Flnstra. SPECIMEN This specimen appears to combine 42. to a great extent, the characters of S, tenella, Aider, and S.fmiformis, Hincks. The stem is very zig-zag, the angles formed being almost right-angles. The receptacles are too short for S. fusiformis, and although appar- ently smooth, in most instances this is pro- bably due to the age of the specimen, as in some specimens they are wrinkled. The rim is four-toothed. The capsules are oval, ribbed, and with dentate apertures, but in many cases they appear plain. It is a pretty little species and nearly allied to S. rugosa. Diphasia rosacea, 2 dry specimens, and 2 specimens in boxes. SPECIMENS This a most delicate and 43,44,45,46. elegant species. It is generally found trailing over hydroids and PLATE V. E. C. Photo, ad nat. Sertularia pumila, Li On steins of Fuscus serratus. (Three-fourths nat. size.) DIPHASIA ROSACEA. 69 other objects, throwing up stems, curving and tendril-like towards the tips, which grasp any object for support. Side branches, which hardly differ in size from the stems, are given off alternately; the receptacles are tubular and occur on both sides of the stem oppositely. The apertures are furnished with a lid or operculum. The capsules differ in each sex ; the male is cylindrical in shape, lobed lengthwise, and surmounted by a crown of spines ; the female is somewhat pear-shaped, with a supplementary chamber for the maturing ova, and with two prominent incurved spines at the crown. Specimens showing both forms of capsule are exhibited in the glass-topped boxes. Common in the trawl. Sertularia pumila, Linnaeus. (PLATE V.) 2 dry specimens on sea-weed. SPECIMENS Sertularia pumila covers with 47, 48. great profusion, various sea- weeds between mid and low tide. It is of a stronger and closer build than S. gracilis, but shorter and more branching, the branches often being 70 BRITISH HYDROID ZOOPHYTES. opposite. The receptacles are tubular and opposite ; the capsules are ovate, tapering to a short pedicel. There is a slight collar to the aperture. Very common. Sertularia gracilis, Hassan. I dry specimen, and 1 specimen in box. SPECIMENS -A- species of particularly fine 49, 5O. habit. It is symbiotic on other hydroid stems, over which it grows, throwing up short and fine stems. The receptacles are opposite and tubular, the rim being sharp. The female capsule is ovate with a narrow collar-like aperture. They may be seen on the specimen in the glass-topped box. Not common. Sertularia operculata, Lmmeus. (PLATE VI.) 2 dry specimens, and 1 specimen in box. SPECIMENS The stem of this species is very 51, 52, 53. delicate, branches distantly in a dividing manner, and produces colonies of enormous extent, and luxuriant in growth. It has been called the " sea hair" hydroid. The PLATE VI. E. C. Photo, ad nat. Sertularia operculata, Linnaeus. On stems of Laminaria. (Six-tenths nat. size.) The Scale is 10 Cm. SERTULAKIA ABIETINA. 71 receptacles are tubular and are arranged oppositely on each side of the stem ; the outer lip of the margin being very sharp and pointed. The capsule is somewhat balloon-shaped, with a plain aperture. It is often symbiotic on Laminarian stems and Mussel valves. It would hardly be venturing too far to say, that the colony here shown on the Laminarian stem (see plate VI.) probably equals innumber the population of London. The previous species might be regarded as a dwarfed form of the present; S. operculata, however, is vastly more profuse in its growth. It is common in the trawl. Sertularia abietina, Linnaeus. 4 dry specimens, and 1 specimen in box. SPECIMENS This species has been 54, 55, 56, 57, 58. popularly called the " Sea-fir." The main stem grows to a considerable height, and throws out alternate lateral branches which in some specimens branch again. The receptacles are sub-opposite ; the capsules are ovate, 72 BRITISH HYDROID ZOOPHYTES. wrinkled, and slightly tapering at the base. Often grows upon scallop valves and on rocks. Trawled from rather deep water. Sertularia argentea, Ellis and Soiander. 2 dry specimens, and 1 specimen in box. SPECIMENS This is a very elegant species. 59, 60, 61. The stems produce alternate short branches, each branch giving out other short branches in a palmate manner. The receptacles are sub-opposite and sharp-tipped. The capsules are somewhat shield-shaped. Trawled from moderately deep and very deep water. This species, and S. cupressina are often chosen for decorative purposes. Sertularia cMpressina, Linnaeus. (PLATE VII.) 2 dry specimens. SPECIMENS Somewhat like the last species in 62, 63. habit, but the stem is much longer and more tapering. It throws out short branches, mainly alternately, which immediately fork and re-fork in a palmate PLATE VII. E. C. Photo, ad nat. Sertularia cupressina, Linnaeus. (Three-fourths nat. size.) HYDRALLMANIA FALCATA. 73 manner, as in the previous species. The receptacles are sub-opposite and directed forward. The outer lip of the aperture is sharp and pointed. Receptacles and stems both have a slightly compressed appearance. The capsules are of an elongated shield shape, the upper corners being prolonged into spines; they are numerous on the specimens exhibited. Not uncommon in the trawl, or thrown upon the shore. Hydrallnmnicb falcata, Linnaeus. 3 dry specimens and 1 specimen in box. SPECIMENS The stem *s l°ng an(^ spirally 64, 65, 66, 67. twisted, giving off alternate, regular, pinnated, palm-like branches, each pinna or side-branchlet bearing on its inner side only, the jug-shaped receptacles, which are crowded together. The capsules are oval, with a slight collar to the aperture. The spiral stem gives to this species a specially graceful character. Very common in the trawl and often along the shore. 74 BRITISH HYDROID ZOOPHYTES. Family— PLUMULARIID.E. Antennularia antennina, Lmneeus. (PLATE VIII.) 2 dry specimens and 1 in liquid. SPECIMENS This species has been well named 68, 69, 7O. the " Antenna-like " hydroid. It throws up long, straight stems, and at short intervals, gives out in nodes, like the plant Equisetum, short, fine, radiating branches, bearing on the upper side only, shallow tea-cup-like receptacles. Nematophores are plentifully distributed, one on either side above, and one below each polypite, with others on the stem. The capsules are oval with an oblique truncated aperture. They may be seen on the specimen preserved in liquid, likewise the fine branches and receptacles. This species is generally found growing on scallop valves in deep water, and is common off Hastings. Two very curious species of Nudibranch Molluscs, Doto Coronata and D. pinnatifida, feed upon the polypites, and also attach their spawn to the stems. PLATE VIII. E. C. Photo, ad nat. Antennularia antennina, (Four-tenths nat. size.) The Scale is 10 Cm. ANTENNULARIA KAMOSA. 75 o d Fig. 13 — Transverse section of stem of Antennularia ramosa, Lamarck. (Magnified). (a b c). — Tubes opening into one another, (d). — Dart sack from coenosarc. Antennularia ramosa, Lamarck. (PLATE IX.) 2 dry specimens, 1 specimen in liquid. SPECIMENS This species does not attain so 71, 72, 73. great a height as the last ; the stems, also, branch frequently, although 76 BKITISH HYDROID ZOOPHYTES. somewhat irregularly. The stems and the branches throw out at the nodes, delicate radiating offshoots, bearing receptacles on the upper sides. These are similar to the receptacles of the last species, but the nodes are much closer, and there is some variation in the distribution of the nematophores. The capsules are horn-shaped, a drawn out and curved variation of those of the last species. The stem and branches of this species will repay microscopic examination. A transverse section (see fig. 13) shows many other tubes of various shapes and sizes running parallel with, and arranged around, the main tube, pressed tightly against each other, and annealed together. Many of these tubes open into those adjoining and into the main tube ; the ccenosarc, therefore, is uninterrupted. Not uncommon on the scallop valves in deep water. Aglaophenia pluma, Linnaeus, (PLATE X.) 2 dry specimens, also 1 in liquid and 1 in box. SPECIMENS After storms, when sea- 74, 75, 76, 77. weed in large quantities is thrown upon the beach, A. pluma may fre- quently be found on Halidrys siliquosa, PLATE IX E. C. Photo, ad nut. Antennularia ramosa, Lamarck. (Five-sixths nat. size.) PLUMULARIA PINNATA. 77 It winds its loose mesh of fibres around stem and branches, and throws out, in every direction, graceful, pinnated plumes, which resemble fronds of tree-fern or palm. The receptacles which are somewhat cup-like, with the margin irregularly dentate, are borne on one side only of the axis. The nematophores are confined to the region of the receptacles, and their peculiar movements are worth attention. The capsules in this, and some other species are additionally protected by a modification of the palm-like branches ; the delicate side branches being folded around the capsule to which they are united. These " ribs " are studded with nematophores. Plumularia pinnata, Linnaeus- (Figs. 14, 15.) 3 specimens in liquid. SPECIMENS A very lovely and delicate species 78, 79, 8O. of a semi-transparent, white hue. The creeping base throws up stems regularly and alternately branched, which, towards the apices, curl over like a feather. The receptacles are arranged along the upper side of the branches. The gonophores are crowded 78 BRITISH HYDROID ZOOPHYTES. Fig. 14 — A polypite of Plumularia pinnata ex- panded and gorging a worm ; also enlarge- ments of tentacle and dart cells in situ. En- larged. (a).— The polypite. (b). — A portion of a tentacle. Much enlarged. (c).— Eight dart cells, in situ . Magnified. The first operation on the part of the polypite was to throw out a number of darts, and then to get the tail end of the worm between the tentacles and gradually draw it down into the stomach. Owing to the mucus on the body of the worm, the darts did not appear to affect it much, and after the lapse of half -an-h our, it was still living, although its tail end was probably being digested in the stomach of the polypite. PLATE X. LIVING. E. C. Photo, ad nat. DEAD. Aglaophenia pluma, Linnaeus. On stems of IFalidn/s siliquosa. (Both half nat. size.) PLUMULARIA PINNATA. 79 together on the main stem. They are somewhat pear- shaped and lobed lengthwise, and project more or less into spines in the upper part. Hinck's descrip- tion of this species appears to be rather too re- stricted. There is some difference be- tween the deep sea and the shore forms, and he pro- bably gave more attention to the former variety. In the beautiful specimen of the shore variety exhibited, several joints occur between the polypites ; and the nematophores are more generally distributed than one would expect to find from Hincks' description. In a - Fig. 15— (a).— A polypite of Plumularia pinnata (enlarged). b). — Showing amoeboid bodies (" nematophores.") (c).— Polypite. 80 BRITISH HYDROID ZOOPHYTES. the shore variety, there is one nematophore above and one below each polypite, and in many cases, either one or two in the axils of the branches. There seems also to exist considerable variation in the development of the capsular spines, so that one can hardly help recognizing the close connection of the three species, pinnata, echinulata, and similis. A rather poor specimen of the deep sea form is exhibited. This form is somewhat rare, but the shore variety is common in rock pools from mid to low tide. Plumularia setacea, Ellis. 1 specimen in liquid on Antennularia stem. SPECIMEN Extremely delicate, branches at a 81. less open angle than the last species; the capsules are elongated spindle shape, quite distinct from other forms, and are produced in the axils. They are decidedly the best specific character Nematophores plentifully distributed. Rare at Hastings. Not observed as a shore form. GONOTHYR^KA LOVENI. 81 A:-. Fig. 16 — GoUOthyrsea Loveni, Allman. Enlarged. (After Hincks). (a).— Alimentary polypite. (b).— That which represents the " select " polypite. (c). — The "reproductive" bud in various stages of maturity, the most matured containing ova. In this case it fails to become detached. (d). — The horny receptacle, or " capsule," (o).— Ovum. 82 BRITISH HYDROID ZOOPHYTES. GLOSSARY. Alimentary polypite. The polypite whose only duty is to obtain and assimilate food. Athecata. The word means " sheath - less," and is applied to the Lower Division of the Hydroida, in which the poJypite is not protected by a horny receptacle, as in the Higher Division. Capsule. Strictly; speaking, the well formed horny receptacle or case which encloses in the Thecaphora all that represents the " select " polypite, together with the reproductive buds containing the ova. It is often applied to the whole body thus represented. Coenosarc. The word means " common flesh," that is, that portion of the compound animal structure, in the Hydroids, which is common to, or which connects, the individual polypites. Gonophore. The reproductive bud with its envelope, as occurring in the Athecata, and where it is distinct from the polypite or bud which bears it. GLOSSARY. 83 Nematophore. The word signifies " thread-carrier," in allusion to the threads, or tubes of the darts with which the nematophores are often associated. They are peculiar amoeba-like bodies (sometimes called " guard-polypites "), and are found associated with polypites, and also on the stem and branches in the Plumulariidse. Planule. The larval form into which the egg, after segmentation, develops, prior to its transformation into the polypite. Reproductive bud. Special egg, or seed-bearing buds. "Select" polypite. Certain of the alimentary polypites told off* to bear the special reproductive egg-producing buds, and which are generally more or less modified in consequence. Thecaphora. The word means " sheath -bearer," and is applied to the Higher Division of the Hydroida, in which the polypites are provided with a horny receptacle. ANNOTATIONS — MADE BY P. B. IN — "A History of British Hydroid Zoophytes," — BY — THOMAS HINCKS, B.A. While looking through some of Mr. Rufford's books, I have been much interested in perusing the annotations made by him on the pages. Many of the remarks are exceedingly brief — simply three or four words — others are of the nature of a short sentence, while a few are somewhat lengthy. A very large number occur in the " Manuel de Conchy liologie," they do not, however, bear directly upon the Oonchological section, p. 107, et seq. in this book. Those which are of most interest at the present moment, are written on the pages of Hincks' " History of the British Hydroid Zoophytes." I have thought that several of the more important annotations may prove of interest to the general reader as well as of value to the student of Hydromedusse. It has been necessary to quote from the text of Hincks' work somewhat extensively, but only so much as to preserve a continuity of idea, and to show the application of P. R.'s remarks. Page XL, line 12 from the bottom. Concerning Thread-cells in Ectoderm of Coenosarc and Gonophore, Hincks writes: " The thread-cell is a most interesting piece of structure Two kinds of thread-cell are often met with on the same species. Besides ANNOTATIONS. 85 the formidable instruments with which the tentacles are armed, large, bean-shaped cells are sometimes crowded together in immense quantities, as, for example, in the ectoderm of the ccenosarc in Hydranihea^ and in the outer covering of its gonophore. It is difficult to imagine what relation these can bear to the economy of the animal." To this Mr. Rufford adds the following : " The thread-cells on Ectoderm of Ccenosarc and Gonophore may be of service when some member of colony is defunct ; as I have frequently seen Infusoria, etc., invade the space between Ccenosarc and polypary, having obtained access through the decay of one or more polypites. In some cases, however, I believe the decaying end is closed." P. R. Page XIX., line 9 from the top. " In the genera Hydr actinia and Podocoryne. . . . some curious appendages occur in addition to the alimentary polypite. . . . We have first the spiral bodies." These Mr. Eufford designates as " Snake-like zooids in Hydr actinia." The place of development of these appendages, and the energy they display is then described in the text. At the end of this , aragraph "They usually form a somewhat dense fringe round the mouth of the shell [which is almost always* tenanted by a Hermit crab], and are roused from *The words " almost always " are underlined with pencil. 86 BRITISH HYDROID ZOOPHYTES. their state of quiescence by anything that may irritate the surface of the Coenosarc," this marginal note appears : " Is there any exception ? and what evidence is there that the crab has not just left the shell?" P. R. Page XXL, first 25 lines. In the margin at the side of the section dealing with the reproduction of a Hydroid colony; the following is written : " In Thecaphora, buds reproductive spring from Coenosarc and are protected. In Athecata, buds usually developed on body, but sometimes on Coenosarc, and are unprotected." "Buds borne on special zooids which become atrophied and then resemble the capsuled gonophores of the Thecaphora." The latter note is more of the nature of a summary of a portion of the text, than the expression of a new idea. It is, however, instructive and interesting. Page 24, line 14 from the top. With reference to the habit of Hydractinia echinata, Hincks states that it occurs on univalve shells tenanted by Hermit crab. A marginal note states : " Also on the claws of lobster." P. R. This is probably a unique, or at least, unusual, situation for Hydractinia echinata. Page 103, line 5 from the top. Appended to the habitat of Garveia nutans, is the following footnote : ANNOTATIONS. 87 " Hastings.* Polypite (wholly) and coenosarc carrot-red, Polypary transparent, colourless (like water), more or less faintly annulated. Branches wriggling and springing from stolons entwined on stems and branches of Hydrallmctnia. No gonophores. End of March, '95." P. E. Page 119, line 12 from the bottom. Tubularia coronata, Abiidgaard. The following appears in the margin of p 119 : " This species appeared suddenly on the Hastings shore in the latter part of 1897, and was very abundant, but a storm about the end of the year destroyed all the colonies. — I obtained some of the gonozoids which were shed, in a glass vessel, without persuasion. They were very inactive, not knowing whether to stand on their base or on the tentacles, but rather preferred the former. Alternate tentacles were raised or lowered, The tentacles are knobbed, (p. 120). In the Hastings specimens, there appeared to be very little * Signifies that Mr. Ruff ord had discovered this species in Hastings district. Three specimens in liquid are exhibited in Hastings Museum, see also p. 48. 88 BRITISH HVDROID ZOOPHYTES. branching, if any. I never saw this specimen here [i.e., at Hastings] before." P. R. "KB. —The knobbed tips to tentacles of gonozoid fixed it as this species." For illustration and description of this species see plate II., Fig. 10, and pages 49-53 of this volume. Page 295., line 10 from the top. Plumularia pinnata, Linnams. " Shoots clustered, tall, white, or of a pale horn-colour," etc., etc., Hincks. Marginal note : " I have found some specimens a bright yellow to orange. Here and there, however, the ends of pinnae were colourless." P. R. Ibid, line 3 from tlie bottom. "The calycles of Plumularia pinnata are only separated by a single joint, those of Plumularia setacea by two." Hincks. An asterisk at the word " joint," draws attention to the following footnote : " Not always, by any means, in the shore variety at Hastings, although it holds good, to a great extent, with the deep sea form/' P. R. Hincks, continuing the description of this species remarks (p. 296, line 7 from the top) : "A much safer criterion (as regards distinctive marks of the species) is to be found in the nematophores, which are scantily developed and exhibit a very peculiar structure/' , ANNOTATIONS. 89 " This will not hold good, either, for the shore form at Hastings (specimens with well matured gonophores) shows a nematophore above and one below each polypite, and often This does not appear to accord with Mr. Rufford's investigations, as the following footnote on the same page indicates. one or two in the axils of the branches. Moreover, there is considerable latitude in the degree in which spines are developed on the gonophores." P. E. Also in the letterpress of the same page (line 13 from the top) it is stated: "When present, the reproductive capsules afford another good specific character ; " Mr. Rufford's observations had led him to regard the reproductive capsules as "the best" specific character, and noted such in the margin (line 9 from bottom), he also added, " The deep-water specimens are of the larger size .... and differ in other respects." There are a few other marginal comments, such as "common in trawl," "on other Hydroid stems," and numerous summaries of paragraphs, which, however, would serve no useful purpose if quoted. PART III. NOTES ON POLYZOA, OR BRYOZOA 1. PLATE XT. E C. Photo, ad nat. 2. 1. A typical Polyzoon. Flustra foliac3(i, (Half nat. size.) 2. A typical Bryozoan. Lepralia foliacea, Ellis and Soiand (One-third nat. &ize.) PART III. — AN INTRODUCTION — TO — POLYZOA. OR BRYOZOA. SUB-CLASS L— ECTOPROCTA. Anus outside Tentacle stage. Order L — Gy mnolaemat a (Holobr an ch iate) , No Epistome. Tentacle stage circular. Sub-Order 1 — Gyclostomata. * Cell mouth circular, no door (operculum). Sub-Order 2 — Cheilostomata. Cell mouth with lip-like door. Sub- Order 3 — Ctenostomata. Mouth of Cell cut into narrow segments closing aperture. Order II. — Phylactolaemata(Pterobranchiate). With Epistome, tentacle stage with arms. SUB-CLASS II.— ENDOPROCTA. Anus within the tentacle stage. No Epistome. Tentacle stage an imperfect circle. * Cell or zoosciuin. 92 INTRODUCTION TO POLYZOA. The word Polyzoa signifies an association of animals. The group are thus termed on account of their habit of forming extensive colonies, by a process of budding, such buds being permanently retained in organic connection. Form of Polypide. The Polypide, or Zooid, as the individual Polyzoon is variously termed, is minute, and may be generally described as having a body more or less oval in form, consisting mainly of a body-wall, and an alimentary canal suspended within it. With the exception of a few not altogether undoubtful forms in Entoprocta, the polyzoa are capable of withdrawing inwards one end of the body, thus forming a kind of funnel, at the bottom of which lies the mouth ; and around it are arranged ciliated gill-tentacles. These tentacles, when the retractile end of the animal is thus withdrawn, lie within the funnel-shaped depression, and it is therefore known as the tentacle sheath. The mouth leads into a tube which is a prolongation of the funnel wall, and represents the oesophagus, or commencement of the alimentary canal. ALIMENTARY CANAL. 93 Alimentary canal. From a point, either just outside (Ectoprocta), or just within (Entoprocta), the tentacle stage, there arises another tubular extension of the funnel, or body-wall, pendant and parallel with the other tube. This corresponds with the intestine and stomach, and united to the other tube at the supposed free ends, forms with it the complete alimentary canal, commencing with a mouth and terminating in an anus. Tentacle stage circular. The alimentary canal is therefore suspended like a loop from the bottom of the funnel, or anterior end of body. In the great majority of the Polyzoa, the tentacles are arranged in a circle around the mouth (Holobranchia), but in some, mostly from fresh water, the circle is not complete, but side arms are thrown out, the tentacle stage then taking the form of a horse-shoe with the ends more or less prolonged (Pterobranchia). Body cavity. Between the body-wall and the alimentary canal is a space called the body cavity. This is filled with a transparent 94 INTRODUCTION TO POLYZOA. fluid containing corpuscles, which, probably, subserve excretion. In some instances part of the cavity is ciliated. Body-wall structure. The structure of the body-wall is as follows : The outer layer is a horny cuticle (Ectocyst), and is secreted by an inner layer of cells (Epidermis, or Endocyst). Next come two layers of muscular tissue (Parietal muscles), the first arranged circularly and the other longitudinally. Finally, there is lining the whole of the body cavity, including the exterior of the alimentary canal, an unequal layer of cellular tissue (Coenosarc or Parenchyma) from which are derived the parts which connect the various members of the colony. In some of the Polyzoa (Cyclostomata and Cheilostomata), the external layer of the body-wall is strengthened by a shelly deposit, and, in a few instances, it is gelatinous. The obsolete word cell is applied here to this protective outer covering, as simpler than the accepted term Zooecium. Alimentary canal structure. As regards the structure of the Alimentary canal, it is lined internally by an epithelium of NERVOUS SYSTEM. 95 ciliated cells (Endoderm), and externally by the coenosarcal layer (Ectoderm), which also lines the body cavity. There appears to be also an intermediate layer of a muscular character. Nervous system. The nervous system is represented by a single or bi-lobed ganglion (collection of nerve-cells), situated on the wall of the oesophagus, within the body cavity, and upon the anal side. It sends out nerves to the tentacular crown, oesophagus, reproductory organs, and elsewhere. Muscles. The chief muscles are the Retractor muscles for withdrawing the mouth and tentacles within the sheath ; the muscles connecting the stomach with the body-wall (Gastric muscles); the muscles connecting the base of the stomach with the body-wall and termed the Funiculus. Lastly, the muscles which line the body-wall, (Parietal muscles), used for reducing the capacity of the body cavity and thus everting the mouth and tentacles. The muscles are of a very rudimentary character, being single and barred, and when relaxed hang loosely like threads of cotton. 96 INTRODUCTION TO POLYZOA. Reproduction. There are two methods of reproduction obtaining, one method asexual, the other sexual. Asexual reproduction. The asexual method, or process of producing permanent buds, results in the formation of colonies (colony budding), each bud being connected with its parent by a thread or network of threads derived from the cellular layer of tissue lining the body-cavity, and by the protective cuticle and its epidermis. In a few instances, the body-cavities of adjoining polypides are openly connected. In many cases, the polypide cells of a colony are more or less distant from one another, each polypide being connected by a stem-like prolongation (Stolon). In other cases the polypide cells abut upon one another more or less compactly. Colonies are formed either over running objects, adhering to them, such as shells, stones, seaweed, etc., or growing erect and branching, thereby producing plant-like structures, with either cylindrical or laminar stems and branches. In the families Selenariidse of CHEILOSTOMATA and Cristatellidse SEXUAL REPRODUCTION. 97 of PHYLACTOL^MATA the colonies are loco- motive, the former moving by the aid of " Vibracula," and the latter with a creeping motion. Loxosoma non-colonial. InLoxosoma (Endoprocta) we have the only known single Polyzoon. In this genus, buds are formed, but detach early. It is found commensal on marine worms. Besides the colony budding, bads called " Statoblasts " are formed on the Funiculus and detached, being set free only on the decay of the Polypides. Sexual reproduction. In the sexual method of reproduction, each individual possesses both male and female elements. These are situated within the body-cavity, the ovaries on the body- wall in the upper part of it, and the male cells on the Funiculus. Both elements are formed by a modification of the cells of the coenosarcal layer lining the cavity. In only a few species does there appear to be any exit from this cavity It is therefore inferred that fertilization usually takes place within it. At the same time, it is has been 98 INTRODUCTION TO POLYZOA. observed that the elements often come to maturity at different periods. It is likewise inferred that the embryo only escapes after the break up of the Polypide. In Alcyonidium there occurs an " intertentacular pore," and in Pedicellina and Loxosoma there have been discovered ciliated tubes (? nephridia) connect- ing the body-cavity with the exterior, and evidently subserving excretion. Ovicells in Cyclostotnata. In one group of the Polyzoa (CYCLOSTOMATA), the Polypide cells become modified into special chambers (Ovicells), for the rearing of the embryos. Ovicells in Cheilostomata. In another group (Cheilostomata), there occurs at the head of the Polypide cell an inflation of the cell- wall, forming a recess of the body- cavity, in which the embryos are lodged during maturation. It is termed an Ovicell. The forms and markings of these Ovicells are very good guides for specific determination. Operculum in Cheilostomata. In the same group of Polyzoa (Oheilostoinata), the mouth of the Polypide cell is furnished OPERCULUM AND AVICULAPJUM. 99 with a horny door or valve (operculum) for closing the entrance, and somewhat resembling a lip. Hence, the name of this group Cheilostomata, signifying " lip-mouthed." This door (or operculum) plays an important part in the economy of this group, since it gives rise to two very curious and interesting modifications, viz., the Bird's-head organ and the Vibraculum. Operculum in Ctenostomata. In another group (Ctenostomata), the margin of the cell mouth is cut into numerous fine segments, like the teeth of a comb. When the tentacles of the animal are withdrawn, the points of the segments meet overhead so as to close the aperture. The word Ctenostomata means " cut-mouthed " in allusion to this form of operculum. An analogous contrivance may be found in the operculate Hydroids. Avicularium. In certain of the Polyzoa (Cheilostomata), there occurs an organ called the Bird's-head organ (Avicularium), since in its higher form it resembles very strikingly the head of a bird. It is a peculiarly interesting example of modification, and one 100 INTRODUCTION TO POLYZOA, in which the ultimate results attained are so utterly unlike the origin, that were not all the various stages of evolution traceable, it would have appeared incredible that this organ should have originated, as it has done, in the ordinary Polypide and cell. To describe, then, briefly, this peculiar organ, which occurs only in that group of the Polyzoa in which is found the lip-like door, viz., the Cheilostomata. In examining (with the microscope) the colonies of certain species, some members are found to differ somewhat from the ordinary members. The cell becomes gradually reduced in size and the aperture with its door becomes larger in proportion to the cell area, and also modified in form, approaching somewhat to the shape of a bird's beak. The size of the cell becomes still further reduced until it is quite small comparatively with an ordinary cell. The cell outline now becomes partly or wholly obliterated, and the cell commences in consequence to lose its identity as a distinct cell, and gradually becomes merged in a neighbouring one. The Polypide has become aborted, but well-developed muscles occupy its former position. These serve for opening VIBRACULUM. 101 and closing that which was formerly the door of the cell, but which is now more appropriately termed the mandible, since it is seen to be continually opening and shutting, with a sharp snap, and often with some minute creature, in its grip. It seems probable, therefore, that the function of this organ may be t<> .protect' the colony from hostile intruders. Vibraculum. There is yet another departure, a further modification of the Bird's- head organ, to be described. It consists in a further development of the mandible, and its adaptation, evidently for a different purpose from that of prehension. The mandible becomes greatly prolonged, to such an extent that it has more the appearance of a sword or stick, guarding the various members of the colony with which it is associated. The idea is borne out by the circumstance that this sword or Vibraculum, as it is called, is constantly waving from side to side. If this vibracular organ be now compared with its point of departure, viz. : the Polypide and cell, one can hardly fail to be struck by the 102 INTRODUCTION TO POLYZOA. wonderful plasticity of nature, as evidenced in this example of the specialization of the individual. Epistome. There is one organ which has hitherto not been described, since the majority' of Polyzoa are distinguished by its absence. This organ is the " Epistome," a hollow lobe of the body-wall, overhanging the mouth upon the anal side. It is ciliated and appears in one marine species to aid the animal in ascending its tube, thus performing a function similar to that of the molluscan foot, of which it is regarded the precursor. The group of the Polyzoa in which the epistome occurs is called the Phylactolaemata. Classification. The three most important distinctions in the Polyzoa are : 1. — Whether the anus lies outside (Ectoprocta) the tentacle stage, or within it (Endoprocta). 2. — Whether the organ known as the Epistome be absent (GYMNOL^MATA*), or present (PHYLACTOLJEMATAf). *Signifies "naked-throat," i.e., without epistome. t Means "throat-guarded," i.e,, with epistome. AFFINITIES. 103 3. — The form of the tentacular stage, i.e., whether it be circular (Holobranchia) as in the GYMNOL^EMATA, or like a horse-shoe (Pterobranchia), as in the PHYLACTOL^MATA. Considerations 2 and 3 concern the Ectoprocta. The Entoprocta are few, and of rather doubtful position as regards the Polyzoa. In them there is no Epistome, and the tentacle stage is neither a complete circle nor thrown out into arms. In some species (Loxosoma), there is a pedal gland comparable to the peduncle in the Brachiopoda. Affinities. The Polyzoa appear to be cut off* by absent forms from very near ancestors. Perhaps the nearest approach to their structure is to be found in the ROTIFERA, which are microscopic water animals, sometimes single, sometimes compound, and either fixed or free. At the oral end of the body there is a ciliated disc, capable of withdrawal. They have an alimentary canal and anus, a bladder and water vascular system. There is also a 104 INTRODUCTION TO POLYZOA. distinct body-cavity, and the individuals are unisexual instead of bisexual, as in the Polyzoa. PHRONIDEA and BRACHIOPODA. Above the Polyzoa in point of structure the PHYLA PHRONIDEA and BRACHIOPODA, are placed. In these, the chief point to be noted is the modification of the tentacle-arms, which are coiled up and supported by an internal shelly skeleton. In addition to being organs of touch, they also subserve aeration. In the BRACHIOPODA there is a ventral and dorsal shell, and the animals are never compound. MOLLUSCA. When the Polyzoa are compared with the Mollusca proper, it is found that the latter, with their well-formed heart, extensive nervous system, and several other features, are so far in advance that the gap is remarkable. It can hardly be doubted, however, that there are in the lamellar gills, and foot of the bivalve mollusc, the homologues, respectively of the tentacular crown, and the epistome of the Polyzoa. P. J. E. TABLE OF POLYZOA. 105 TABLE D. Systematic Table to show the Classification — OF THE — PHYLUM POLYZOA. CLASS I— ECTOPEOCTA. Anus outside the tentacular circlet. Order. L— GYMNOL^EMATA. Ectoprocta with circular lophophore, without epistome. Sub-order 1 — Cheilostomata. The orifice of the zocecium can be closed by an operculum. Avicularia, vibracula, and ovicells, are often present. TRIBE A.— CELLULAEINA. TRIBE B.— FLUSTKINA. 8 Families. 4 Families. TRIBE C.— ESCHAEINA. 12 Families. 106 INTRODUCTION TO POLYZOA. Sub-order 2 — Cyclostomata. Zooecia tubula, with a plain terminal orifice without operculum. Without movable appendages. The ovicells are modified zooecia. TRIBE A.— AETICULATA. TRIBE B.— INAKTICTJLATA. 1 Family. 4 Families. Sub-order 3 — Ctenostomata. When the tentacle-sheath is retracted, the orifice of the zooecium is closed by a folded membrane as by an operculum. Zoarium never calcareous. Ovicells and appendages absent. TRIBE A.— HALCYONELLEA. 3 Families. TRIBE B.— STOLONIFERA. 7 Families. Order //.— PHYLACTOL^EMATA. Fresh-water Polyzoa with horse-shoe-shaped lophophore and epistome. FAMILY 1— CKISTATELLID^E. FAMILY 2~PLUMATELLID^B. CLASS II— ENDOPEOCTA. Anus within the tentacular circlet. Arranged by & & After SEDGWICK. I PflRT IV. CONCHOLOGICAL • NOTES. PLATE XII. E. C. Photo, ad nat. Prepared by P. J. R. Immature Shell of Rostellaria curtirostris, Lamarck. Median longitudinal division. Portion of spire missing. (Nearly nat. size.) 107 PflRT IY. CONCHOLOGICAL NOTES. Although the plates (Nos. XII. -XVII.) contained in this part are more or less self-explanatory, they appear to require a few notes in further elucidation of the specimens they illustrate. It may also be acceptable to the reader if a reason is stated for their introduction. For some time prior to his decease, Philip James Rufford directed his energies to the preparation of several series of type specimens of shells, each of which illustrates some special feature in the structure of molluscan coverings. In so doing, he recognized, and exemplified the dictum, that if a Museum is to fulfil its highest purpose as an educational factor, every exhibit, or group of exhibits, must be employed as an object lesson. With this plan in view, he had arranged, and labelled many specimens, in a manner best calculated to arrest the attention of an observer, and direct it towards any special point in the construction of the abode or the anatomy of the animal producing and inhabiting it ; and it has been thought that these series are of sufficient importance to merit the notice of all persons interested in such work. They may also serve as ensamples to any naturalist contemplating the formation of similar series. They must not be regarded as exhaustive and final, nor complete in every detail. An exhibition on a scale such as will allow the introduction of each characteristic of the structure, growth, peculiarities, etc., of Univalve, Bivalve, and Multivalve shells, requires a very large number of specimens, embracing world- wide distribution of species ; many months of labour to name, label, and arrange in systematic order ; and also ample accommodation for effective exhibition. Such is not expected in a provincial Museum. 108 CONCHOLOGICAL NOTES. Tiie specimens are exhibited in one of the table cases in the Hastings Museum. There is little doubt that the arrangement in which they now appear was not intended as final ; additions would have necessitated various alterations of positions. Among the additions intended were univalve shells in sections, showing such features as the columella, the sutures, the whorls, the inner and outer lips, and also the anterior and posterior canals. One such specimen is illustrated in plate XII. It is exhibited in the same case as the other descriptive shells. The anatomy of molluscan animals was also receiving treatment, two creatures having been mounted in preservative fluid in glass museum jars. The animals producing bivalve shells are represented by the animal of Anodontacygnea, Linnseus, the fresh- water Mussel, deprived of its valves, and so displayed as to show the mantle, mouth, foot, gills, and other organs, in an interesting and instructive manner. The other specimen is the animal of Buccinium undatum, Linnseus, the Common Whelk, illustrative of the univalve group. It has been most cleverly treated and arranged. Deprived of life while in the act of crawling, various portions of the body — the proboscis, syphon, tentacles, etc. — are fully displayed in a very natural manner, allowing the anatomy of the creature to be easily observed and studied. Upon the exterior of the jars small labels are affixed, each label having a slender prolongation, terminating at the part named. It has been thought that these, as also the series of shells, on account of the educational value of both, are worthy of reproduction in the present work. The circular shape of the jars, unfortunately, detracts somewhat from the distinctness of the objects and the lettering. THE BIVALVE SHELL ft. ITS PARTS Prepared by P. J. R E. C. Pholfcegnat. , V 1 1'' < \ -c A tjj^ lc/(?tt^ jBiydklye; Shell, and its parts. Biibwing ihe Margins, Eidges, Umbones, Ligament, Linula, Ears, Accessory Plates, and the Periostracum. (All one-third nat. size.) THE BIVALVE SHELL. 109 PLATE XIII. The Bivalve shell, and its parts. Some of the principal lineaments of a Bivalve shell are the dorsal, ventral, anterior, and posterior margins ; pibs, ridges, and spines; the umbones; the ligament; the linula; projecting portions known as the ears ; the accessory plates ; and the periostracum. The Margins determine the contour of the valves. They are clearly shown in fig. 8. The Ribs radiate from the umbones to the anterior, posterior, and ventral margins, figs. 4, 4a, plate XIV. ; the Ridges are arranged in concentric form, and coincide with the lines of growth, they can be seen in fig. 1 ; Spines vary greatly in length, thickness, and shape, some are slender and pointed, others narrow, thin, long, flat, or, plicated, and project at various angles. The Umbones, fig. 1. The umbo of each valve originates as the embryonic shell, and forms the point from which the growth of the valve proceeds. The Ligament, figs. 1, 3, is an elastic structure, consisting of two parts, an external horny substance, and an internal substance of very similar character, known as the Cartilage, both of which act as a hinge, and hold the valves together. Figs. 3, 3a, and plate XTV. The Linula is a part usually oval in outline, in the form of a depression in front of the umbones, fig. 1 . The Ears, figs. 3, 3a, 5, are known as anterior and posterior. They are elongated portions of the dorsal margin of the valve. Accessory plates are small valves which protect the dorsal margin. In the common Piddock (Pholas dactylus\ the number is five. 110 CONCHOLOGICAL NOTES. The Periostraeum, fig. 8, is the horny cuticle, or so-called epidermis. It is secreted by the free edge of the mantle. It varys considerably in thickness ; on some shells it is thin and soft, on others thick, coarse, or drawn out into long, beard-like filaments. It protects the shell from the action of erosive chemical substances, and the adverse conditions of weather. The important internal features of a bivalve shell are the anterior and posterior adductor muscle impressions; the hinge-teeth; the pallial line and sinus. In several genera of the BRACHIOPODA (which have recently been isolated as a distinct PHYLUM) there is a branchial skeleton, which, when in the form of a loop, is supported by a calcareous process of the dorsal valve ; but as a spiral form it is devoid of a support. The Muscle impressions indicate the points of attachment of the adductor muscles. These muscles pass through the body transversely, and by contraction, keep the valves closed at the will of the animal, during which time the cartilage is compressed. When the tension is relaxed, the valves gape by reason of the expansion and counter-action of the cartilage. The Hinge-teeth. These are of two kinds. The cardinal teeth, which are situated immediately beneath the uinbones, and those on either side of the cardinal, named the lateral. Figs. 4, 4a, plate XIY. In the genus Area, the teeth are very numerous, 35—42 ; in many other genera (Pecten Ostrea, and others), they are absent. The Pallial line, and the Sinus, figs. 2, 2a, 7, 7a. The former is the line of attachment of the pallial muscle of the mantle- edge to the shell, the curve (the sinus) in its outline, is known as the pallial bay, or indentation, and it permits the syphons, when retracted, to be contained within the closed valves. PLATE XIY. CARTILAGE TS ARRANGEMENT THI HINCE-TEETH E. C. Photo, ad nat. Prepared by P. ?. R The Cartilage, and its arrangement ; and The Hinge-Teeth. (All one-third nat. size.) THE CATTLAGE, AND HINGE TEETH. Ill PLATE XIV. The Cartilage, and its arrange- ment; and The Hinge-Teeth. The cartilage of Scallop and Oyster shells is in the form of a triangle, with the apex directed towards the umbo. It is of a resilious nature, but when dry, exceedingly hard and unyielding. It varies considerably in shape, size, and the position it occupies. See also descriptive labels in the plate. " The ' Ligament ' is a thin horny, inelastic band connecting the hinge of each valve ; it is wedged within a cleft in the Shell and is often more or less connected with the ' Cartilage.' The * Cartilage ' is of a somewhat similar substance, but is thick, compact and fibrous, and occupies a 'pit.' Its action is to keep the valves open, in opposition to the Adductors. It differs chemically from the 'Ligament.' " Figs. 1, 1 A.— Valves of Pecten. "In Pecten the Ligament runs the whole way along the hinge-line, the Cartilage being central. Figs. 2, 2A. — Valves of Anomia. '•' Cartilage carried upon a process." Figs. 3, 3A.— Valves of Ostrea. " In the Oyster there are no Hinge-teeth." Figs. 4, 4A. — Valves of Cardium. "Lateral teeth, Cardinal teeth." Figs. 5, SA. — Valves of Pholas. " In Pholas there is no Cartilage." Figs. 6, GA.— Valves of Tettina. " Cartilage- shelf perpendicular." Figs. 7, 7 A.— Valves of Solen. " Cartilage carried upon a shelf." PLATE XV. _*f**tJtetii*;/&$y. . 3!tellJ*1a7~e* oCMim are ense &. irrt m ft ni ca&es xrtf/, frit*. -ft&'fLs <£i/fer&.. 11 Budding of Medusa 26 123 142 61 Calcareous limestone 137 113 Calcareous spicules 113 Ik 115 Calcareous sandstone 138 ussel 115 Calycella syringa 61 84 . . 108, 115 Calyptoblastea .. Campanularia vertidllata 33 59 111 Campanulariidae 10,53 74 Capsule 25,64 43 63 75 Carbonate of lime 115 32 Cardinal teeth .. 111 115 116 Cardium 111 113 Cartilage, The 109, 111 110 Cartilage-shelf .. 111 106 Cell mouth 91 96 Cellularina 105 131. 135 Channels 18 .'.' 10, 35, 82 Cheilostomata .. 91, 105 47 Chitin 10 25 Chiton, Animal of 113 105 Chiton, Shell Plates of . . 113 99 Chitonidse 113 Cilia.. 17 Ciliated epithelium 118 19, f.n. 55 Circulation by cilia 12 19 Circulation of nutriment . . 12,13 127 Classification of Polyzoa . . 102 99 Clava multicomis 35 109 Clavidae 35 108, 115 Clavatella f.n. 18 24 Clytia 56 137, 138 Clytia Johnstoni 53,54 INDEX. 145 Cnidaria Coat of mail Ccelenterata Coenosarc Collar cells Colony budding Common Piddock Common Whelk Conchological notes Conchyplm Coppinia arcta . . Coppiniidae Coral polyps Coriaceous mantle Cornea Corrigenda Corynidae Coryne vagina . . Craspedota Cristatellidse Crocodile Ctenic Ctenidium Ctenostomata Cyclops Cyclostomata Dart cell Darts Dart sack Dispersal Development of bell Dioecious Diphasia rosacea Division of labour Dot o coronata . . Doto pinnatifida Ears .. Ecclesbourne Echinata Ectocyst Ectoderm Ectoprocta Endocyst Endoderm Endoderm cell .rage 32 Endoprocta 113 Epidermis 35 Epistome . . 8, 10, 82 28 Epithelial prominences Equisetum 7, 96 Escharina 119 Eudendriidae .. 108,115 Eudendrium rameum 107 Eudendrium ramosum 115 Eulamellibranchiata 43, 64 Excretory organs 63 9 113 Fairlight 116 143 Fairlight Clays . . Fertile polypite . . 35, 44 44 Filamentary rods Filaments 32 96, 106 Filellum serpens Filibranchiata .. 137 Filices f.n. 14 Filicinae 113 119 Flagella 116, 119, 120 Flesh particles . . 91,106 Flustra 44 Foot .. 91, 106 Flustrina Form of polypide Formation I. 37 Formation II. . . 5 Formation III. . . 37 Formation of bud 13 Foulness 17 Freshwater Mussel 116 Freshwater Polyzoa 68 Funiculus 16 74 74 Garveia nutans . . Gastric muscles. . Gastropoda 109 General remarks 125, 139, 142 Gills .. .. 41 Glossary 94 Gonoblast 5 Gonophore 91, 105 94 Gonophores Gonothyrsea Loveni 6 Gringer 37 Gringotter 146 INDEX. Guard polypites Gymnoblastea . . Gynmolfemata .. Pafe 32 91, 105 Halcyonellea .. .. 106 Haleciidse .. .. 63 Halecium .. .. 24 Halecium halecinum . . 63 Halecium Beanii . . 66 Halidrys siliquosa . . 76 Harebell .. .. 10 Hastings Museum . . 108 Hermit Crab . . . . 41, 85 Hinge-teeth .. .. Ill Hollow connexion . . 12 Holobranchia . . . . 93, 103 Hybodus .. .. 137 Hydra .. .. 8 Hydra vulgaris .. .. 38 Hydracorallinae . . . . 32 Hydractinia . . . . 29, 85 Hydractiniidse .. .. 39 Hydractinia echinata . . 39, 42, 86 Hydrallmania .. . . 48, 87 Hydrallmania faleata . . 73 Hydrida .. .. 32 Hydroida . . . . 32, 35 Hydroids .. .. 32 Hydroids and Polyzoa compared 30 Hydroids compared with Coral polyps .. .. 29 Hydroids compared with Sea- anemones . . 29 Hydroids compared with Sponges 27 Hydromedusee .. .. 32 Hydrozoa .. .. 32 Iguanodon Inarticulata Indentation Infusoria Interfilamentary junctions Interlamellar junctions Introduction Iron-clay-stone .. Ironstone isopleura 135, 136 106 110 43,85 118, 119 119 xx. 134 136 113 Jaws Jelly-fish Jelly-fish hatches eggs Junctions Lafoea dumosa , . Lafoea parvula . . Lafoea pocillum Laf oeidge Lamellibranch, A Lamellibranchiata Laminarian stem Larva, an Amoeba Larva, a Medusa Larva, a Planule Larva, a polypite Laterals Lateral teeth Lenses Leptoinedusae Leptosporangiatse Ligament Lithocysts Lobster Lovenella clausa Loxosoma Page 115 21,22 22 117 62 62 62 62 119 115, 119 71 27 27 27 27 116 111 116 33 141 109, 111 20, f.n. 55 39, 86 47, 60 97, 98, 103 Mantle . . 116 Mantle-cavity . . 119 Mantle-fold . . 113 Margins . . 109 Medusa . . 6 Muscles . . 7 Mesenteries . . 30 Mesoderm . . 6, 7 Mesoglaea . . 6, 37 Mesozoic plants . . 141 Methods of dispersal . . 23 Modification of reproductive bud .. .. 25 Modification of select bud 24 Modification of select polypite 15 Mollusca . . . . 104, 113 Muscles .. .. 95 Muscle of attachment . . 116 Muscle impression . . 110 INDEX. 147 Naked throat . . Narcomedusae . . Nature of budding Nematophore . . Nematophores .. Nephridia (?) . . Nerves Nerves and Muscles Nervous system Nucleus Nucula nucleus . . Obelia Obelia dichotoma Obelia gelatinosa Obelia geniculata Obelia longissima Object of circulation Ocellus Odontophore (Esophagus Oospheres Opercularella lacerata Operculum Ophiodes Optic nerve Oral tentacles . . Order of reproduction Organs for seeing Ostrea Ova set free Ovaries in body-wall Ovaries in Medusa Ovicells Ovum Oyster Pallial bay Pallial line Palps.. Parenchyma Parietal muscles Parkeria Part I. Part II. Part III. Part IV. PartV. Page Page f.n. 102 Pecten 111 33 Pedal gland 103 7 Pedicellina 98 83 Pelecypoda 117 11, 13 Perigoniums repens 47, 55 98 Periostracum 110 7 Permanent budding 13 20 Pholas 111 95 Pholas dactylus .. 109 37 Phylactolsemata 91, 106 47 Phyronidea 104 Pinites Ruffordia 125 Pinites Solmsi .. 127 56 Placophora 113 59 PlanulaB 17, 22, 23 57 Planule 83 56 Plumatellidse 106 58 Plumularia 11 13 Plumularia echinulata 80 f.n. 55 117 Plumularia pinnata 78, Plumularia setacea 79, 80, 88 80,88 115 Plumularia similis 80 f.n. 14 Plumulariidse 11, 41, 74 61 98 Podocoryne Polyp 85 f.n. 9 41 Polypary, The 9 116 Polypide f.n. 9 50 Polypite f.n. 9 15 Polypite receptacles 10 19 Polyzoa 9,91 111 Polyzoon 92, 97 23 Primordial nervous system 21 26 Probocis 116 26 Process of budding 26 98, 105 Protective resemblance 8 37 Protobranchiata 119 111 Pseudopodia 6 Pterobranchia 93 Pterobranchiate 91 110 110 •i ~i x Pterodactyl Pteridophyta 137 141 llo 94 Purbecks " 133 94 29 1 Rachidian . , 116 35 Radiating canals 18 91 Radula 116 107 Receptacle lid . . 11 131 Reproduction . . 96 148 INDEX. Reproductive bnd Reproductory organ Retina Retractor muscles Ribs Ridges Ripple marks . , Romanes Rotifera Rufford collection Euffordia Ruffordia Gopperti Page 15. 17, 22, 83 116 116 95 109 109 135 20 103 123 125 141 Scallop .. Schizaceae (?) .. Sea-fir .. Sea-hair .. Secondary tentacles Select buds .. Select polypite . . , SelenariidaB . . Septa.. .. Septibranchiata.. Sertularia abietina Sertularia argentea Sertularia cupressina Sertularia gracilis Sertularia operculata Sertularia pumila Sertularella fusiformis Sertularella Oayi Sertularella polyzonias Sertularella rugosa Sertularella tenella Sertulariidae .. Sexes of reproductive bud Sexual reproduction Shell-plates of Chiton Shore Hydroids.. Sinus.. .. Siphonophora .. Skeletal framework Skeleton, The .. Snake-like zooids Solen.. .. Solitary polypites Specialized individuals Specimen 1 .. 2,3 .. Ill 141 71 70 19 23 14, 83 96 30,117 119 71 72 72 70 70 69 68 67 6ft 67 68 66 16 97 113 57 110 33 9 9 85 Ill 16 35 39 Specimen 4, 5 6,7 .. 8,9,10,11 12 .. 13, 14, 15 16, 17, 18, 19 . . 20,21.. 22 .. 23 .. 24 .. 25, 26, 26A 27 .. 28 .. 29, 30, 31 32, 33 34, 35, 36, 37. 38 39, 40, 41 42, 43, 44, 45,46.. 47, 48 49, 50, 51, 52, 53 54, 55, 56, 57, 58 59, 60, 61, 62,63.. 64, 65, 66, 67 . . 68, 69, 70 71, 72, 73 74, 75, 76, 77 . . 78, 79, 80 81 .. Spermarium .. .. Spines Statoblasts Stinging apparatus Stolon Stolonifera Structure of polypite Structure of typical Hydroid Syphon Systematic table of Ccelen- terata Systematic table of Ectoprpcta Systematic table of Hydroida Systematic table of Polyzoa Systematic table of Pterido- phyta Swimming-bell Table A Table B Table C Page 44 45 46 47 48 49 53 56 57 INDEX. 149 Page Page Table D 105 Umbones Table E 141 Univalve shells . . .. 108 Tellina 111 Tentacle stage Tentacles 93 116 Vascular Cryptograms 141 Thecaphora 10, 53, 83 Vascular tissue . . 120 Thread cells 84, 85 Veil .. 18, 21, f.n. 55 Throat-guarded Tooth ribbon f.n. 102 116 Vibracula Vibraculum .. 97,105 101 Trachomedusae 33 Trigger hair TubulariaB Tiibularia coron Tubularia indiv Tubulariidae Two methods of ata isa dispersal 37 32 49,87 49 49 17 Wadhurst Clays Wealden catalogue Wealden flora . . Wealden formation Whelk shell . . 131, 138 . . 126, 128 141 133 41 Two rings of nerves 20 Zooecium .. f.n, 91 Umbo .. .. 109 UNIVEKSITY OF CALIFORNIA LIBRARY, BERKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. Books not in demand may be renewed if application is made before expiration of loan period. 50m-7,'27 681343 BIOLOGY LIBRARY UNIVERSITY OF CALIFORNIA LIBRARY