Si asese eS Seba Hot) euranpaticateh aes pt PEO tt oa ides sed oeatags Py Ips hoe, ‘ ie ete e Os i Au a Oe aots fe Gat ee my Ate eA ie ar pasate heel tt: irae ie, wee De oe 4s, ROL “* ere ses SA ay ar ay, .e CAP pha Seat es i iH 4 4 Hee }: se ay ee pied is agit 4 id ten py ate () ‘iba, ie coe ees a eh b HeSt3¢ peheary es: rin aheeyi ak Hy ihe prapepee pt ace y| tA, ee lees 1? beads * > rata atalint at slay dod bera anne! a eaoatetltay at 5 eh ba each Pat teM) ies Eee setae aanosnis snes Capac i DOS ICA SUNY nestepata rest 3 ah oe ett, *! eens oo se Mutou i i} Hee Bh tats ra ee) 4) Hotes fe NR i fl it ea Hide ds Otte ie Uiaie pF Gi i op ¥ a ety Nestor oon Me be iy (dy oe) ‘) its iy igi ete . 4 Kees ap Moths boge PIS FaPS OEARSS ato yviots 3 TA ia tiered Nl th Pie hasnt ‘ pasts ai cH es rata) i re soos $54) MM Ain br teed abe nance Be it i CEH tt He ciety it i i ean peabl ee let Bina Tiel ear Hiya et yt ie i lt aK y! ih Ki (; : 4 i hat ele iain rae ret He EDA eat ye Mur Ms Humes iH 8) a ih Bia eis Oeiss Ct) Spr by Ag ratiie o Liat? if aii eeyay asia : eee bi 4 i ALBERT R. MANN LIBRARY AT CORNELL UNIVERSITY jonograph of the British Spongiadze. Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http:/Awww.archive.org/details/cu31924003410986 THE RAY SOCIETY INSTITUTED MDCCCXLIV. This volume is issued to the Subscribers to the Ray Society for the Year 1865. LONDON: MDCCCLXVI. GW ie A MONOGRAPH OF THE BRITISH SPONGIADA, BY J. 8. BOWERBANK, LL.D., F.RS., F.LS,, ¥.G.S,, F.2.S., F-BAS., MEMBER OF THE ENTOMOLOGICAL SOCIETY OF LONDON; OF THE MICROSCOPICAL SOCIETY OF LONDON; CORRESPONDING MEMBER OF THE DUBLIN UNIVERSITY ZOOLOGICAL AND BOTANICAL ASSOCIATION; OF THE PLYMOUTH INSTITUTION, AND DEVON AND CORNWALL NATURAL HISTORY SOCIETY, ETC, ETC. VOL. II. LONDON: PUBLISHED FOR THE RAY SOCIETY BY ROBERT HARDWICKE, 192, PICCADILLY. MDCCCLXVI. A, ad PRINTED BY J. E, ADLARD, BARTHOLOMEW CLOSE. This Volume is Juserided, WITH GREAT RESPECT, TO THE MEMORY OF THE LATE DR. GEORGE JOHNSTON, OF BERWICK-ON-TWEED, AN ENTHUSIASTIC AND TALENTED OBSERVER AND WRITER ON ~ NATURAL HISTORY; WHOSE NUMEROUS WORKS ON BOTANY AND MARINE ZOOLOGY, AND ESPECIALLY ON THE SPONGES AND ZOOPHYTES OF GREAT BRITAIN, HAVE POWERFULLY AIDED IN THE DIFFUSION OF A TASTE FOR THE CULTIVATION OF THOSE SCIENCES. PREFACE, In the first volume of this work, page 159, in the ‘Tabular View of Systematic Arrangement,’ I included the exotic as well as the native genera ; believing it highly probable that some of the species of the former would before long be found among our British Sponges ; and this idea has been already realised, by my having since that period added two species of Heionemia and one of Ophlita- spongia, an entirely new genus, to our list of British species. I have followed the same course in the synopsis of the genera in this volume, but to prevent any misconception regarding the British Genera, I have given a list of those which are described in this volume, with the number of species in each, in the Table preceding the synopsis of the Genera. Generally speaking, there is no great difficulty in the determination of the genus, but in some cases more than ordinary caution is necessary in the examination of the specimen under consideration. The greatest difficulty in this respect lies in the determination of specimens belong- ing to the first section of Halichondria, and the first of Isodictya. In the former, the structures are so loosely and irregularly reticulated, as to render it very difficult to dis- tinguish between them, and some specimens of the latter, viii PREFACE. without the section for examination be very carefully made from a specimen in a good state of preservation, and correctly at right angles to the surface ; but in all cases of the examination of a specimen, the last observation should be especially impressed on the memory. In the synopsis of the Genera I have endeavoured to give the student every facility for references to the letter-press and plates of the first volume of this work, and this is the more necessary, as the terminology adopted in the generic and specific descriptions is to a great extent new to this branch of Natural History. ‘his facility of reference will, I trust, aid the student materially in his examinations of both genera and species that may be new to him. Notwithstanding my long and intimate acquaintance with the species of British Sponges, such is their extreme variations in colour, size, and form, especially in the dried state, that it has frequently occurred that I have failed to recognise specimens of some of the commonest species, until I have submitted them to a regular microscopical examination ; and indeed there are some that so closely resemble each other, in all their external characters and habits, as to render such an examination absolutely neces- sary to the correct determination of the species. I have therefore deemed it necessary, not only to render the genera as distinctly recognisable as possible, but also when the number of species In a genus are numerous, to again divide and subdivide them by means of the peculiarities of the spicula of the skeleton, so as to facilitate the labour of the determination of the species within the smallest possible range, for the convenience of the student. To effect this purpose, I have divided, when necessary, each genus into PREFACE, ix sections, determinable by the forms of the spicula; and each of these sections are again divisible, into those which have the spicula smooth, and those which are furnished with spines. I have considered the sections and sub- sections into which the genera are thus divided as per- manent divisions, applicable to all the genera alike; the sections being distinguished by one, two, three, or more asterisks, and the sub-sections are indicated by letters. The species in some of these divisions and subdivisions are already very numerous, as at the present time we have in the genus Hymeniacidon 42, in Halichondria 28, and in Isodictya 43 species; and I believe these divisions and subdivisions to be the more necessary, as from the quantity of new species I have lately received, there is every appearance that the number of British Sponges will be greatly multiplied by the researches of naturalists before many years shall have elapsed. I have not adopted the extensive list of synonyms of the British species given by Dr. Johnston, as I have good reason to believe that many of them are unavoidably very doubtful; I must therefore beg to refer the reader, who may wish to enter upon an investigation of that portion of their history, to that learned author’s ‘ History of the British Sponges,’ &c. Thus the references to habitats of Hymeniacidon ficus, carnosa, and suberea, are rendered very uncertain, from the habit each has of simulating the forms assumed by the other two, and also from species having hitherto been established from external form only, while each individual varies exceedingly in that character at different periods of its development, and in accordance with the necessities induced by the peculiarities of its locality. The wide diffusion of the species renders it un- x PREFACE. necessary to publish each separate habitat ; I have, there- fore, in a great measure, confined the list to those which are within my own personal knowledge, and that of my friends who have kindly supplied me with specimens for examination, except in a very few cases. CONTENTS. A MONOGRAPH OF THE BRITISH SPONGIADA. PAGE PREFACE . 5 ‘ ‘ ' . vil List oF British GENERA OF SPONGES ‘ ; . &K SYNopsis OF GENERA ‘ ‘ : : 1 Order 1. CaLcaREa : F ‘ ; a Ve Grantia . : : : to CLT compressa : ; F se ciliata : ‘ ; . 19 ensata : : : » 25 tessellata . : : . 26 Leucosolenia . F ‘ ; . 28 botryocides ; ‘ . 28 contorta . : .” 29 lacunosa ; ‘ . 382 coriacea ¥ ‘ . 84 Leuconia : ‘ ; . 86 nivea i : ‘ . 86 fistulosa . ; : . 89 pumila . ; ; . 41 xii CONTENTS. PAGE Leucogypsia ; : 42 Gossei ; : ; . 42 Order 2, SILICcEA 45 Geodia ‘ , : : . 45 Zetlandica . : : . 45 Pachymatisma ‘ ‘ ; . 61 Johnstonia : . 61 Ecionemia : ; ‘ : . 55 compressa ‘ . . 55 ponderosa. : . 56 Polymastia : ‘ ‘ . 58 ornata : : A . 658 bulbosa : . 61 robusta ‘ ; . 62 brevis : . 64 spinula ‘ ‘ . 66 radiosa ‘ ; . 68 mammillaris ; ‘ GAL, Halyphysema ‘ . : . 6 Tumanowiezii ; : . 6 ramulosa : ‘ . 79 Ciocalypta ; ‘ ; . 81 penicillus : ; . 81 Tethea . : : . _ 83 cranium ‘ ‘ : 83 Collinsii ‘ ; : _ 87 Schmidtii . ; . . 89 lyncurium . ; . _ 92 spinularia . : _ 94 Halicnemia . ( : _ 96 patera : : . 96 Dictyocylindrus : : : . 100 CONTENTS. xili PAGE Dictyocylindrus—continued. ventilabrum . ‘ . 100 ramosus : . 108 radiosus : . 105 Howsei ; : . 106 hispidus : ' . 108 aculeatus : . 109 fascicularis . : . 110 virgultosus , : . 118 pumilus . ; . 114 stuposus : : . 116 rugosus ‘ : . 119 Phakellia i : : g . 120 robusta . : : . 120 ventilabrum . “ i . 122 Microciona < ‘ ; . 124 fictitia ; ; : . 124 levis . ‘ j . 127 fallax ; 3 P . 128 armata . ‘ . . 129 spinulenta . 3 é . 182 carnosa : ‘ . 183 ambigua sg i : . 186 atrasanguinea , . 188 Hymeraphia . . : . . 141 vermiculata ; ; 141 clavata : , ‘ . 148 verticillata ‘ , . 145 stellifera . ‘ j . 146 Hymedesmia ; : : . 149 radiata ‘ : : . 149 stellata F : . 150 Zetlandica . ‘ ‘ . 152 Hymeniacidon . : : . 154 Thomasii . ; . . 155 xiv CONTENTS. PAGE Hymeniacidon—continued. coccinea . : . 156 Brettii ; ‘ ‘ . 158 fragilis i : . 159 reticulatus , . 159 fallaciosus : F . 160 albescens . ‘ : . 161 lactea P . 168 perarmatus . ‘ . 164 membrana i , . 165 caruncula ‘ : . 166 sanguinea : : . 168 mammeata F ‘ . 170 consimilis : ‘ . 172 variantia . : : . 174 macilenta j : . 176 fallax ; : ; . 177 veridans_ . : . 178 perlevis . ; ‘ . 179 aurea : ‘ . 181 armatura . ‘ : . 183 pachyderma : , . 184 crustula . : ‘ . 185 lingua : ‘ . 187 floreum . : ‘ . 190 virgultosa : ; . 198 plumosa_ . 7 : . 195 jecusculum . : . 198 suberea ‘ ; . 200 carnosa : . 2038 ficus ; i ; . 206 sulphurea : : . 208 subclavata ‘ . . 209 clavigera . : ; . 211 celata i : : _ 219 CONTENTS. Hymeniacidon—continued. Halichondria Isodictya gelatinosa paupertas Dujardinii Bucklandii panicea glabra angulata . caduca inconspicua incerta coalita distorta corrugata . Thompsoni forcipis simplex subdola incrustans candida irregularis Dickiei Pattersoni pulchella . Ingalli scandens . Batei granulata . Hyndmani nigricans albula farinaria . inornatus xXV PAGE 222 223 224 226 228 229 232 233 234 236 237 238 240 242 243 244 246 247 249 251 252 253 - 255 256 258 259 261 262 264 266 268 269 271 273 xvi CONTENTS. PAGE Isodictya—continued. cinerea . . : . 274 Peachii : - «276 permollis 278 simulo : : . 279 varians . 281 rosea , . . 282 elegans . : 283 McAndrewii . ‘ . . 284 indefinita : 286 parasitica ; : . 287 indistincta . 290 densa, F ; 292 anomala . : . 293 simplex ; ‘ 294 jugosa s i . 296 pallida ; k : . 297 fistulosa ; 299 Gregorii , : ‘ . 801 fallax : é : . 802 robusta F ; F . 804 pocillum . ‘ ‘ . 805 mammeata . : ; 306 simulans : ‘ . 808 dichotoma . ; , 309 palmata : . 38ll pygmea : : ‘ . 313 ramusculus : . . 3814 clava ’ 4 316 infundibuliformis . : . 3817 dissimilis i : , . 3818 Normani é : . 3820 fucorum . ; : . 822 Alderi . : . . 3823 Edwardii 2 : . 325 CONTENTS. xvii PAGE Isodictya—continued. lobata . ; : . 826 paupera : ; ‘ . 328 uniformis , ‘ . 829 Clarkei 2 : 2 . 830 gracilis ; F . 3831 Barleei : : ; . 883 Beanii.. : : . 3884 lurida . . : . 886 fimbriata . : . 887 Spongilla : ‘ : ; . 839 fluviatilis : : . 339 lacustris . F 2 . 842 Desmacidon ‘ : . 845 fruticosa . ; é . 845 Jeffreysii : . 847 Peachii F F A . 849 constrictus ‘ ; . 850 eegagropila . i . . 852 Rapbyrus ‘ : : . 854 Griffthsii . : : . 854 Diplodemia . ‘ . 857 vesicula ; : : . 857 Order 3. KERATOSA ‘ ; . 359 Spongionella . ‘ ‘ ‘ . 859 pulchella 5 , . 3859 Chalina : : 5 . 861 oculata i , . 861 cervicornis : : i 364 Montaguii . i : . 3866 Flemingii : : i . 3870 gracilenta . ‘ . 872 Xvili CONTENTS. PAGE Chalina—continued. limbata : ‘ 373 Grantii ; 4 : . B75 seriata 376 Ophlitaspongia : ‘ ; . 378 papilla . ‘ : . 3878 Verongia ‘ . : . 380 Zetlandica j ' . 3880 Dysidea . ‘ : . . 381 fragilis . : ae . 3881 xx A LIST OF BRITISH GENERA OF SPONGES, WITH THE NUMBER OF SPECIES IN EACH. Grantia, Leucosolenia Leuconia Leucogypsia Geodia Pachymatisma Ecionemia . Polymastia Halyphysema Ciocalypta Tethea Halicnemia Dictyocylindrus Phakellia Microciona Hymeraphia Hymedesmia Hymeniacidon Halichondria Isodictya Spongilla Desmacidon Raphyrus Diplodemia Spongionella Chalina Ophlitaspongia Verongia Dysidea Order 1,—CacaREA. Order 2.—St1LIcEA. Sub-Order 1 Shib-Odar 2 Sub-Order 3 ” Sub-Order 4 Sub-Order 5 Order 3.—KERATOSA. Sub-Order 1 Sub-Order 3 Sub-Order 4 Sub-Order 7 BH Ow H PONPEHEAFENN MEE Noe cm 43 A MONOGRAPH OF THE BRITISH SPONGIADA. SYNOPSIS OF GENERA. Crass—P ORIFERA, Grant. Orper I.—CALCAREA. Genera. 1. GRANTIA. 2. LEUCOSOLENIA. 3. Lzvconta. 4. Leucoeypsia. 1. Grantia, Fleming. Sponge. Furnished with a central cloaca, parietes con- structed of interstitial cells, more or less regular and angular in form, disposed at right angles to the external surface, and extending in length from the outer to very near the inner surface of the sponge, where each terminates in a sing'e osculum. Vol. J, p. 162. 1 2 A MONOGRAPH OF THE ‘Type, Grantia compressa, Johnston. Vol. I, Plate XXI, Figs. 312, 813, and Plate XXVI, Figs. 345, 346, a, 6. 2. Levcosouenta, Bowerbank. Grantia, Fleming and Johnston. Sponge. Fistular. Formed of a single layer of triradiate and other spicula, surrounding a large central cloaca," which extends into all parts of the sponge. Vol. I, p- 164. Type, Grantia botryoides, Fleming. Vol. I, Plate XXVI, Figs. 347, 348. 3. Leuconia, Grant. Grantis, Fleming and Johnston. Sponge. Furnished with cloace, one or more. Parietes of sponge formed of a mass of irregularly disposed interstitial membranes, and triradiate and _ other spicula; permeated by sinuous excurrent canals, the oscula of which are irregularly disposed over the surfaces of the cloacee. Vol. I, p. 164. Type, Grantia nivea, Fleming. Vol. I, Plate XXVII, Figs. 351, 352. 4. Leucoerrsia, Bowerbank. Sponge. Massive, without cloace; formed of irregularly disposed membranous tissues and spicula. Oscula at the external surface. Vol. I, p. 165. Type, Leucogypsia Gossei, Bowerbank. Vol. I, Plate XXVI, Figs. 349, 350. Suborder I. BRITISH SPONGIADA. ce Orper IJ.—SILICEA. Spiculo-radiate skeletons. Not reticulate. Composed of spicula radiating in fasciculi or sepa- ae rately from the base or axis Geodia, Lamarck. 9. Pachymatisma, Bower- bank. 10. Ecionemia, Bowerbank, Alcyoncellum, Quoy et Gaimard. Polymastia, Bowerbank. Halyphysema, Bower- bank. 14 Ciocalypta, Bowerbank. of the sponge. Halicnemia, _. Bower- bank. Dictyocylindrus, Bower- bank. . Phakellia, Bowerbank. . Microciona,Bowerbank. . Hymeraphia, Bower- bank. . Hymedesmia, Bower- bank. oot Pe Tethea, Lamarck. 1. Gropia, Lamarck. Skeleton. Spicula fasciculated, radiating from the base or central axis of the sponge to the surface. Dermis crustular, furnished abundantly with closely packed ovaria. Ovaria siliceous, composed of cuneiform spicula; firmly cemented together by silex, in lines radiating from the centre of the ovary. Pores fur- nished with cesophageal tubes, terminating in the distal extremity of the intermarginal cavities. Inter- marginal cavities separate, symmetrical, subcylindrical ; each furnished with a membranous valve at its proxi- mal extremity. Vol. J, p. 167. Type, Geodia Barretti, Bowerbank, MS. Vol. I, Plate XXVIII, Fig. 354, and Plate XIX, Figs. 301, 302. 2. Pacuymatisma, Bowerbank. - Skeleton composed near the external surface occasionally of 4 A MONOGRAPH OF THE short fasciculi of siliceous spicula, disposed in lines at about right angles to the surface of the sponge. Central portion of the sponge unsymmetrical. Dermis crustular, furnished abundantly with closely packed ovaria. Ovaria siliceous, formed of cuneiform spicula, firmly cemented together in lines radiating from the centre of the ovary. Pores furnished with cesophageal tubes, terminating in the distal extremity of each intermarginal cavity. Intermarginal cavities sym- metrical, subcylindrical, with a pyloric valve at the proximal end of each. Vol. I, p. 171. Type, Pachymatisma Johnstonia, Bowerbank. Vol. I, Plate XXVII, Fig. 358. 3. Ectonemia, Bowerbank. Sponge. Having a strong axial column or centre of closely packed siliceous spicula disposed in lines parallel to the long axis of the sponge, from which axial column or centre a peripheral system of spicula radiates at about right angles. Distal ends of the radii fur- nished more or less with ternate connecting spicula, the radii of which are disposed immediately beneath the dermal membrane. Vol. I, p. 173. Type, Lchionemia acervus, Bowerbank, MS. Vol. I, Plate XXVIII, Fig. 355. 4. ALCYONCELLUM, Quoy et Gaimard. EvrLectenia, Oven. ‘Sponge fistulate ; fistula single, elongate, without a massive base. Skeleton: primary fasciculi radiating from the base in parallel straight or slightly spiral lines ; secon- dary fasciculi at right angles to the primary ones. Oscula congregated, with or without a marginal boundary to their area. Vol. I, p. 174. = * y) BRITISH SPONGIADA., 5 Type, Aleyoncellum, Quoy et Gaimard. Figures from Zu- plectella aspergillum, Owen. Vol. I, Plate XXIX, Figs. 356, 857. 5. Potymastia, Bowerbank. Skeleton. Basal mass. Central portion consisting of a plexus of contorted anastomosing fasciculi, resolving themselves near the surface into short straight bundles disposed at nearly right angles to the surface. Oscula congregated, elevated on numerous long fistulae. Fistule composed of numerous parallel fasciculi, radiating from the base to the apex of each in straight or slightly spiral lines. Vol. I, p. 177. Type, Polymastia mammillaris, Bowerbank. Vol. I, Plate XXIX, Fig. 358. 6. Hatypuysema, Bowerbank. Sponge. Consisting of a hollow basal mass, from which emanates a single cloacal fistula. Skeleton: spicula of the base disposed irregularly ; spicula of the fistula disposed principally in lines parallel to the long axis of the sponge without fasciculation. Vol. I, p. 179. Type, Halyphysema Tumanowiczii, Bowerbank. Vol. I, Plate XXX, Fig. 359. © 7. Crocatypra, Bowerbank. Skeleton. Composed of numerous closed columns, each consisting of a central axis of compact, irregularly elongated, reticulated stricture, from the surface of which radiate, at about right angles, numerous short, simple, cylindrical pedicels, or stout fasciculi of closely 6 A MONOGRAPH OF THE packed spicula; the distal ends of each pedicel sepa- rating and radiating in numerous curved lines, which spread over the inner surface of the dermal membrane, separating and sustaining it at all parts at a consid- erable distance from the central axis of the skeleton. Vol. I, p. 179. Type, Ciocalypta penicillus, Bowerbank. Vol. I, Plate XXX, Figs. 360, 361. 8. Ternea, Lamarck. Sponge massive, suborbicular. Skeleton consisting of fas- ciculi of spicula. Fasciculi radiating from a basal or excentrical point to the surface. Intermarginal cavities unsymmetrical, confluent. Propagation by internal or external gemmulation. Vol. I, p. 181. Types, Zethea lyncurium, Linneus, and 7. cranium, Lamarck. Vol. I, Plate XX XI, Fig. 362. 9. Hauicnemia, Bowerbank. Skeleton formed of a single superior stratum of spicula radiating from the centre to the circumference of the sponge at about its middle, and of an inferior stratum of spicula distributed without order. Vol. I, p. 184. Type, Halicnemia patera, Bowerbank. Plate XXXII, Figs. 363, 364. 10. DicryocyLinprus, Bowerbank. Skeleton. Without fibre. Composed of a loosely com- pacted columnar axis of spicula, disposed principally in the direction of the line of the axial column, from which a peripheral system of long single or fasciculated BRITISH SPONGIADA. 7 defensive spicula radiate at right angles to the axial column. Vol. I, p. 185. Type, Dictyocylindrus hispidus, Bowerbank. Vol. I, Plate XXXII, Fig. 365, and Plate XXXIII, Fig. 366. 11. PHAKELLIA, Bowerbank. Skeleton. Composed of a multitude of primary cylindrical axes, radiating from a common base and ramifying continuously, from which emanate at about right angles to the axes a secondary series of ramuli, which ramify continuously as they progress towards the surface, but never appear to anastomose. Vol. I, p. 186. Type, Phakellia ventilabrum, Bowerbank. Vol. I, Plate XXXIIL, Fig. 367. 12. Microciona, Bowerbank. Skeleton. A common basal membrane, whence spring at or about right angles to its plane numerous separate columns of spicula intermixed with keratode, furnished externally with spicula which radiate from the columns at various angles towards the dermal surface of the sponge. Vol. I, p. 188. Type, Microciona atrasanguinea, Bowerbank. Vol. I, Plate XXXIII, Fig. 368, and Plate XXXIV, Fig. 369. 13. Hymerapaia, Bowerbank. Skeleton. A single basal membrane, whence spring numerous large separate spicula, which pass through the entire thickness of the sarcodous stratum to or beyond the dermal surface of the sponge. Vol. I, p. 189. o A MONOGRAPH OF THE Type, Hymeraphia stellifera, Bowerbank. Vol. I, Plate XXXIV, Fig. 370. 14. Hymepesmia, Bowerbank. Skeleton. A common basal membrane sustaining a thin stratum of disjoined fasciculi of spicula. Vol. I, p. 190. Type, Hymedesmia Zetlandica, Bowerbank. Vol. I, Plate XXXV, Fig. 871, and Plate XVIII, Fig. 296. Suborder II. Spiculo-membranous skeletons. Composed of interstitial membranes, having the skeleton spicula irregularly dispersed on their surfaces. The prominent character of this Order is that the spicula of the sponges composing it do not assume either the radiate, fasciculate, or reticulate structural arrangement. The distribution of the spicula on the interstitial mem- branes being without any approximation to order. Hymentiacipon, Bowerbank. Skeleton without fibre, spicula without order, imbedded in irregularly disposed membranous structure. Vol. I, p. 191. Type, Hymentacidon caruncula, Bowerbank. Vol. I, Plate XXXV, Fig. 372. Suborder III. Spiculo-reticulate skeletons. Skeletons continuously reticulate in structure, but not fibrous. 1. Halichondria. 2. Hyalonema. 3. LIsodictya. 4. Spongilla. BRITISH SPONGIADA. 9 1. Haticnonpria, Fleming. Sponge. Skeleton without fibre ; composed of an irregular polyserial network of spicula cemented together by, keratode. Vol. I, p. 195. Types, Halichondria panicea and incrustans, Johnston. Vol. I, Plate XIX, Figs. 299, 800, 303, and Plate XXXV, Fig. 373. 2. HyaLonema, Gray. Skeleton an indefinite network of siliceous spicula, com- posed of separated elongated fasciculi, reposing on con- tinuous membranes, having the middle of the sponge perforated vertically by an extended spiral fasciculus of single, elongated, and very large spicula, forming the axial skeleton of a columnar cloacal system. Vol. I, p. 195. Type, Hyalonema mirabilis, Gray. Vol. I, Plate XXXV, Figs. 374, 375. 3. Isopicrya, Bowerbank. Skeleton without fibre ; composed of a symmetrical network of spicula; the primary lines of the skeleton passing from the base or centre to the surface, and the second- ary lines disposed at about right angles to the primary ones. Propagation by internal, membranaceous, aspl- culous gemmules. Vol. I, p. 197. Types, Isodictya palmata and Normani. Vol. I, Plate XXXVI, Fig. 376. 10 A MONOGRAPH OF THE 4. Sponettua, Linneus, Lamarck, and Johaston. Skeleton without fibre, composed of a symmetrical network of spicula; the primary lines of the skeleton passing from the base or centre to the surface, and the secondary lines disposed at about right angles to the primary ones. Reproductive organs, ovaries, coria- ceous and abundantly spiculous. Vol. I, p. 199. All the species are inhabitants of fresh water. The best type of the genus is Spongilla fluviatilis, Johnston. For the structural form of the skeleton, see skeleton of Jsodictya Normani. Vol. I, Plate XXXVI, Fig. 376; and for the ovaries, Plate XXII, Figs. 317, 318, 319, 320, 321, and Plate XXIII, Figs. 322, 323. Suborder IV. Spiculo-fibrous skeletons. Regularly fibrous. Fibres filled with spicula. 1. Desmacidon, -Bowerbank. 2. Raphyrus, Bowerbank. 1. Desmactpon, Bowerbank. Skeleton fibrous, irregularly reticulated. Fibres composed entirely of spicula arranged in accordance with the axis of the fibre, cemented together and thinly coated with keratode. Vol. I, p. 200. Type, Desmacidon fruticosa, Bowerbank. Vol. I, Plate XIU, Fig. 264. 2. Rapuyrus, Bowerbank. Skeleton fibrous, but not horny. Fibre composed of a dense mass of siliceous spicula mixed together with- out order. Vol. I, p. 201. BRITISH SPONGIADS. 11 Type, Raphyrus Grifithsii, Bowerbank. Vol. I, Plate XIII, Fig. 265. Suborder V. Compound reticulate skeletons, having the primary reticulations fibro-spiculate, and the interstices filled with a secondary spiculo-reticulate skeleton. DieLopemia, Bowerbank. Skeleton fibrous. Fibres keratose, hetro-spiculous ; com- bined with a secondary skeleton of irregular network of spicula; rete unispiculate, rarely bispiculate. Ova- ries membranous and spiculous. Vol. I, p. 201. Type, Diplodemia vesicula, Bowerbank. Vol. I, Plate XIV, Fig. 273; Plate XXXVI, Fig. 377; Plate XXIII, Fig. 324. Suborder VI. Solid siliceo-fibrous skeletons. Skeletons reticulate. Fibres composed of concentric layers of solid silex, without a central canal. Reticulations unsymmetrical. Dactylocalyz, Stutchbury =Iphiteon of the Museum Jar- din des Plantes, Paris. DactTyLocaLyx. Skeleton siliceo-fibrous. Fibres solid, cylindrical, Reticu- lations unsymmetrical. Vol. I, p. 203. Type, Dactylocalyx pumicea, Stutchbury. Vol. I, Plate XV, Figs. 274, 275, 276, and Plate XXV, Figs. 340, 341. 12 A MONOGRAPH OF THE Suborder VII. Canaliculated siliceo-fibrous reticulated skeletons. Fibres composed of concentric layers of solid silex, with a continuous central canal. Reticu- lations symmetrical. Farrea, Bowerbank. Skeleton silicen-fibrous. Fibres cylindrical, canaliculated. Reticulations symmetrical, rectangular. Vol. I, p. 204. Type, Harrea occa, Bowerbank, MS. Vol. I, Plate XVI, Fig. 277. Orper II].—KERATOSA. Suborder I. Solid non-spiculate kerato-fibrous skeletons. 1. Spongia, Linneus. 2. Spongionella, Bowerbank. 1. Sponeta, Linneus. Skeleton kerato-fibrous. Fibre solid, cylindrical, aspiculous. Rete unsymmetrical. Vol. I, p. 205. Type, Spongia officinalis, Linneus. Vol. I, Plate XII, Fig. 261, and Plate XXXVIL, Fig. 379. 2. SPoNGIONELLA, Bowerbank. Srone1a, Sowerhy and Johnston. Skeleton kerato-fibrous. Fibres solid, cylindrical, aspiculous. Rete symmetrical ; primary fibres radiating from the base to the apex. Secondary fibres disposed at nearly right angles to the primary ones. Vol. I, p. 206. BRITISH SPONGIADE. 13 ‘ Type, Spongionella pulchella, Bowerbank. Vol. I, Plate XXXVI, Fig. 380. Suborder II. Solid semispiculate kerato-fibrous skeletons. Skeleton partially symmetrical ; primary lines: of fibre radiating from the proximal to the distal parts of the sponge; fibres containing spicula. Secondary lines of fibres unsymmetrical, destitute of spicula. The Bahama sponges of commerce are most of them members of this suborder. Hatuisponeia, Blainville. Skeleton kerato-fibrous. Fibres solid; primary fibres com- pressed, containing an irregularly disposed series of spicula. Secondary series of fibres unsymmetrical, cylindrical, without spicula. Vol. I, p. 207. Types, several species of the Bahama sponges of commerce. Vol. I, Plate XXXVI, Fig. 378. Suborder III. Skeletons kerato-fibrous; fibres solid, en- tirely interspiculous. Skeleton symmetrical. 1. Chalina, Grant. 2. Ophlitaspongia, Bowerbank. 1. CHauina, Grant. Skeleton fibrous. Fibres keratose, solid, cylindrical, and interspiculate. Rete symmetrical; primary lines ra- diating from the basal or axial parts of the sponge to the distal portions. Secondary lines of fibre at about right angles to the primary ones. Vol. I, p. 208. Type, Chalina oculata, Bowerbank. Vol. I, Plate XII, Figs. 262, 263. 14 A MONOGRAPH OF THE 2. Opuiitasponeia, Bowerbank. When the “Tabular View of Systematic Arrangement ’ was published, in page 159, Vol. I, of this work, no sponge, with which I am acquainted, having the structural pecu- liarities of this genus, had been systematically named or described. The spiculated fibres of one Australian and two West Indian species were figured in Plate XVII, Figs. 288, 289, 290, and their structural peculiarities described in pages 275, 276, as instances of the forms and positions of internal defensive spicula. Since this period, in June, 1865, I have received a specimen of a species washed ashore at Vazon Bay, Guernsey, and found with numerous other well-known British sponges, by Mr. Cooper, of Rohais, who presented the greater portion of the specimen to the Rev. A. M. Norman, from whom I obtained it for descrip- tion. It therefore becomes necessary that the genus should be characterised, and added to the other British genera in this synopsis, following that of Chalina in the third sub- order of the order Keratosa, and I propose the following as its characters. Opuuitasponaia, Bowerbank. Skeleton fibrous. Fibres keratose, solid, cylindrical, and exterspiculate. Spicula based on the surface of the fibre, and radiating thence at various angles, either singly or in groups. Rete symmetrical. The type species O. papilla is the only British species with which I am acquainted; but amongst the Australian and West Indian sponges the species are, I believe, by no means few in number. As far as they have yet been examined, they appear all to harmonise with the generic description of the British specimen, but the defensive spicula with which, in all cases, they are profusely furnished BRITISH SPONGIADA. 15 differ in size, form, and mode of arrangement, to so great an extent as to afford the means of very satisfactory specific descriptions. Suborder IV. Simple fistulo-fibrous skeletons. Cavity of the fibre simple, central, and continuous. Veroneia, Bowerbank. Sponeia FIsTULOSA, Lamarck. Skeleton kerato-fibrous. Fibres cylindrical, continuously fistulose, aspiculous. Rete unsymmetrical. Vol. I, p. 209. Type, Verongia fistulosa (Spongia fistulosa, Lamarck). Vol. I, Plate XIII, Fig. 266. Suborder V. Compound fistulo-fibrous skeletons. Central cavity of the fibre single and continuous, having secondary czecoid branches radiating from it at nearly right angles. Avuisxi1a, Bowerbank. Skeleton kerato-fibrous. Fibres aspiculous, cylindrical, continuously fistulose, primary fistule having minute ceecoid canals radiating from them in every direction. Rete unsymmetrical. Vol. I, p. 210. Type, a fragment of the skeleton in the cabinet of the author. Vol. I, Plate XIV, Fig. 268, and Plate XIII, Fig. 267. Suborder VI. Regular semi-areno-fibrous skeletons. Skeleton regular areno-fibrous, having a well-defined 16 A MONOGRAPH OF THE central line of grains of extraneous matter within the fibres. Stematumenia, Bowerbank. Skeleton. Primary fibres solid, more or less compressed, containing a central axial line of spicula and grains of extraneous matters. Interstitial structures abundantly fibro-membranous. Vol. I, pp. 211, 77, 66. Types. Undescribed species in the cabinet of the author. Vol. I, Plate XII, Fig. 256, and Plate XX XVII, Fig. 381. Suborder VII. Irregular and entirely areno-fibrous skele- tons. Skeleton irregularly areno-fibrous, having the skeleton-fibre filled from the centre to the surface with grains of extraneous matter. Dysipga, Johnston. Skeleton. Primary and secondary fibres principally irre- gularly areno-fibrous, occasionally regularly areno- fibrous. Secondary fibres, when destitute of extraneous matters, frequently tubular. Vol. I, p. 211. Type, Dysidea fragilis, Johnston. Vol. I, Plate XIV, Figs. 270, 271, 272. BRITISH SPONGIADA. 17 DESCRIPTIONS oF THE SPECIES. Orper I.—CALCAREA. Genus—GranttA, Fleming. . Grantia compressa, Fleming. — cthata, Fleming. — ensata, Bowerbank. — tessellata, Bowerbank. Se 1. GRANTIA COMPRESSA. Sponge. Compressed, foliaform, slightly pedicelled ; surface even, armed with flecto-clavate spicula. Cloaca ex- panded to the form of the sponge, very large, armed internally with spiculated triradiated spicula; spicular ray short, attenuated. Mouths of cloaca from one to seven or eight, simple, unarmed. Oscula on the sides of the cloaca in depressed areas ; as numerous as the interstitial cells. Pores inconspicuous. Skeleton : spicula equiangular and elongo-equiangulated, tri- radiate, the latter frequently having the two shorter radii exflected. 2 18 A MONOGRAPH OF THE Colour.—Cream white. ; Habitat—Nearly all parts of the British coast ; littoral, or parasitical on fuci to 8 or 10 fathoms deep. Examined.—aAlive. This sponge varies exceedingly in size and shape. In the young condition it is usually more or less of an elon- gated oval form, having a single mouth to the cloaca, at the distal end of the sponge. In older specimens it ex- pands laterally to a very considerable extent, becoming irregularly foliaform and angular at the margin, and at each angle there is usually a mouth to the cloaca. When left by the tide, or in a state of repose, the sides of the sponge are in close contact, and the mouths of the cloaca are closed, but when immersed in water and in full action the sponge becomes considerably distended, and the excurrent streams issue with much force from the mouths of the cloaca. The largest specimen of this species I have seen was collected from the Ipswich River by Dr. W. B. Clarke. It was five in length, and its greatest breadth three and a quarter inches, although of this comparatively enormous size the interstitial cells of the sponge differed very little in their proportions from those of the species of an ordinary size Their diameter did not appear to be in any appreciable degree increased, but their length was nearly double that of the cells of an ordinary sized specimen of the same species. ‘lhe oscula at the proximal termination of the interstitial cells are grouped two or three together at the bottom of irregularly shaped depressed areas, formed by a compact network of triradiated spicula and membranous tissue. The margins of these areas are often furnished with spiculated triradiate spicula, the spicular rays being pro- jected most frequently at a slight inclination towards the mouth of the cloaca, forming to a certain extent a defensive system against intruders within that space, but they are not, as might be expected from the collapsing habit of this sponge, of any great length. The exhibition beneath the microscope of the pouring forth of the excurrent streams from the oscula of this BRITISH SPONGIADA. 19 sponge, and of the vivid action of the cilia within their margins, is one of the most interesting sights afforded by this tribe of animals. ‘The whole of the phenomena at- tendant on this operation will be found described at length in my paper “On the Ciliary Action of the Spongiadz,” published in the ‘ Transactions of the Microscopical Society of London,’ vol. iii, p. 137. It is exceedingly difficult to © get a good view of the pores in this species, they are so completely hidden by groups of flecto-clavate spicula, the distal ends of which curve over the areas in which they are situated, each area being immediately over the distal end of the interstitial cells to which they are appropriated ; they are seen best in half of a young dried specimen, by trans- mitted light and a linear power of about 250. The normal form of skeleton spicula is equiangular tri- radiate, but subject to modification in accordance with the necessities of the parts of the structure in which they are situated ; thus, in those which reach the inner surface of the sponge at the united bases of the radii they radiate in an equiangular direction; the one which passes inward down the sides of the interstitial cells continues straight, but is very much elongated, to give it a firmer hold of the surrounding tissues, while the other two radii, on arriving at the surface, are exflected near the middle of the rays to such an amount as will bury them level with the general plane of the inner surface of the sponge, so that at the basal portions of the radii the spiculum is equiangular, while at the apical portions of two of them they are rectangular, but this mixed form, it must be recollected, is not probably a normal one, but simply a modification of the equiangular triradiate spiculum. 2. Granria ciuiata, Pleming. G. cin1ata, Johnston. —~ PULVERULENTA, Johusion. Sponge. LElongately oval, rarely globular, slightly pedi- celled ; surface papillated, hispid. Cloaca central, 20 A MONOGRAPH OF THE cylindrical, nearly as long as the sponge; armed in- ternally with spiculated, equiangular, triradiate spicula ; spicular ray attenuated. Mouth of the cloaca armed with a thick ciliary fringe, of very long and slender acerate spicula; base of the fringe supported by large, short and stout, fusiform, acerate spicula. Oscula simple, very slightly depressed from the surface of the cloaca; as ‘numerous as the interstitial cells. Pores inconspicuous. Interstitial cells, distal terminations more or less obtusely conical ; furnished with a ciliary fringe of slender acerate spicula. Skeleton spicula equiangular triradiate. Cofour.—Cream white. Hubitat—Coasts of Great Britain, parasitical on fuci, littoral to 8 or 10 fathoms, or more. Ewamined.—Alive. ; This beautiful and interesting little sponge is frequently found associated with Grantia compressa on fuci, either httoral or dredged eight or ten fathoms deep. In the open sea or in littoral localities it seldom exceeds about five eighths of an inch in length, but in tidal rivers, and under some other peculiar circumstances, it attains much larger’ dimensions. Dr. Johnston, on the authority of the late Professor Edward Forbes, figures it (plate xx, fig. 4, ‘History of British Sponges’) three inches in length and three fourths of an inch in. diameter, and I have specimens dredged in the Ipswich river, by Dr. W. B. Clarke, two and a half inches long and half an inch in diameter. These great dimensions are evidently cases of excessive develop- ment, and in the sponges for which I am indebted to Dr. Clarke are probably produced by the large amount of nutriment derived from the drainage of the populous town of Ipswich. In the living condition the surface of the sponge, when examined with a lens of two inches focus, appears to be completely covered with minute conical papillae, from which a few slender sharply pointed spicula are projected. When BRITISH SPONGIADA. 21 dried these conical papilla are transformed into dense pencils of long spicula, and the whole sponge assumes a very hirsute appearance. The bundles of spicula are often seen, in the dried specimens, reclining on the surface of the sponge in every imaginable direction. The cloaca in young specimens is often disproportionately narrow, but in adults it is sometimes one third the diameter of the sponge in width; it is narrowest near the base of the sponge, and gradually enlarges towards its apex. As the sponge has evidently a considerable amount of | expansile and contractile powers, these differences in the diameters of the cloaca may in many instances depend on whether the animal had died in a fully distended or a completely contracted condition. The spiculated triradiated spicula with which the interior of the cloaca is armed are not very numerous, and the points of the defensive rays are usually directed more or less towards the distal end of the sponge. The mouth of the cloaca is profusely furnished with the long defensive acerate spicula; they are very slender and flexible, and often exceed the eighth of an inch in length. At the insertion of their bases into the curving termination of the sponge there is intermingled with them a consider- able number of stout, short, fusiformi-acerate spicula, which renders that portion of the spicula forming the ciliary ring quite inflexible, so that when the mouth of the cloaca is distended by the force of the excurrent stream the ciliary spicula, which in the quiescent state of the sponge were all converging towards its axial line, are now by the distension of the mouth of the cloaca carried into positions, which often exceed those of lines parallel to the long axis of the sponge. ‘The action of the separation or approximation of the distal points of the long defensive spicula is, therefore, simply due to a wise and beautiful mode of insertion into the distal termination of the sponge, and their motions are in no degree dependent on muscular action. Besides the spicular defences of the mouth of the cloaca, I have in two cases found a tense membrane at the base of the neck of the cloacal orifice, entirely closing it, and this 22 A MONOGRAPH OF THE was not merely a clean film that might possibly have been formed by a small bubble of sarcode shed from the animal during or after death, but, like the other membranes of the sponge, there were numerous spicula imbedded in its surface, and in this and in other respects of appearance and position the membranes in both cases were alike. It appears, therefore, probable that, besides the closing of the mouth of the cloaca by the approximation of the distal ter- mination of the ciliary spicula, it has also the power of com- pletely closing it by the extension of a veiling membrane, like that of an osculum. Since the period of my researches into the ciliary action in Grantia compressa J have not had G. ciliata in a living condition, and the precise characters of the oscula are not so readily to be seen in the dried specimens in the latter species as in the former one ; but there is a great similarity between them, and I have little doubt but that if a speci- men of G. ciliata were to be divided longitudinally and placed in a cell with fresh cold salt water, and viewed as a transparent object with a linear power of about 500, the ciliary action would be as readily demonstrated in this species as in G. compressa, as the tessellated cells abound on the inner surface of the interstitial cells to as great an extent as they do in the last-named species. The pores of this sponge are so completely hidden by the cone of defensive spicula that surrounds them that I have never succeeded in obtaining a view of them from the outer surface, but under favorable circumstances, when a section of one of the interstitial cells is made so as to allow of an oblique view of the inside of its conical termination, they are seen to occupy all parts of the cone, and are best observed by the aid of a Lieberkiihn and a power of about 150 linear ; they are tolerably numerous, and I have seen four in the space that would be occupied by one of the tri- radiate spicula. The mechanism of the ciliary appendages of the distal terminations of the interstitial cells is truly simple and beautiful. In the dead specimens we find the ciliary appendages usually closed ; the distal apices of the spicula are brought BRITISH SPONGIADA. 23 together, forming a common point, and within this hollow cone of spicula the distal termination of the interstitial cell may be observed considerably elongated, gradually at- tenuated at that part of its parietes where the proximal ends of the ciliary spicula are attached, and this gradual inclination of the side of the cell towards its long axis necessarily effects a corresponding inclination of the circle of ciliary spicula, thus producing by the simple collapse of the distal end of the cell the same effect that would have been achieved by muscular action in animals of a higher order of structure. In the contrary condition of the ciliary circle of defensive spicula, where they are all projected in lines parallel to that of the central axis of the cell, and forming an open cylindrical tube, we find the part of the cell to which their proximal ends are attached in a fully expanded condition, and the extreme distal end of the cell terminating hemispherically, and sometimes more obtusely. Thus, by the simple and natural act of the inhalation of water and consequent distension of the distal extremity of the interstitial cell, the cone of spicula is expanded into a cylinder, and the ready access of nutritive particles to the pores is promoted ; but the moment that action becomes languid, or ceases altogether, a collapse of the cell ensues, and the distal points of the spicula again approach each other. ‘Ihe distal ends of the interstitial cells are not in contact with each other until slightly below the points of attachment of the proximal ends of their defensive ring of spicula, and in their semi-collapsed condition they bend over in any direction with perfect facility, and this amount of flexibility is thus an effectual safeguard to these delicate but yet brittle defensive organs, the spicula of which are stouter and very much shorter than those surrounding the mouth of the cloaca. The equiangular and triradiate spicula of the skeleton vary considerably in size and form, and one or two of the three rays are frequently more or less curved, to adapt them to the purpose of their position, and occasionally one ray will be considerably longer than either of the other two. I have described and figured the anatomical peculiarities of 24 A MONOGRAPH OF THE this sponge at greater length in a paper published in the ‘Microscopical Journal,’ vol. vii, “Trans. Micr.Soc.,’ p. 79, pl. v. About the year 1841 or 1842 I received from my friend the late Mrs. Griffiths, of Torquay, six specimens of small Grantias, which were designated by her “ Grantia pulveru- lenta, Spongia Ananas of Montagu.” The whole of these specimens agree perfectly with the description of Spongia pulverulenta as given by Dr. Grant, and with Montagu’s description of Spongia Ananas, and the pulverulent cha- racter was apparent on all of them; but on examining them with a power of 180 linear, by the aid of a Lieber- kiihn, I found the pulverulent character arose from their being well-worn specimens, having nearly all the pencils of spicula so prominent in uninjured individuals of all ages and sizes of G. ciliata broken off close to the summits of the interstitial cells, excepting only in parts near the basal attachment, where they had been protected from attrition, and the ciliary defensive spicula of the mouth of the cloaca had suffered in a similar manner. I cut up and examined minutely the most characteristic of these speci- mens, but I could not find the slightest structural differ- ence between it and specimens of well-developed Grantia ciliata, and among the numerous specimens I possess of the last-named sponge I found several that from partial injury presented on one side the pulverulent character, while on the other they were unmistakably G. ciliata. I am therefore inclined to believe that Grantia pulverulenta of Drs. Grant, Fleming, and Johnston, is but a stunted and worn form of G. ciliata, and is, therefore, not entitled to specific distinction. This species runs into a great variety of forms. I have specimens which have assumed the shape of depressed spheres, considerably wider than they are long; others are ovate, and some are seven or eight times their diameter in length ; but in none of these extreme varieties of form have I been able to detect any difference in their structural characters. In some cases the defensive spicula of the inhalent system are rather stouter than in others, but this is probably only an effect of locality. BRITISH SPONGIADA. 25 3. Grantia ensata, Bowerbank. Sponge. Elongately oval, sessile; surface smooth, fur- nished abundantly with large fusiformi-acerate spicula, disposed in lines parallel to the long axis of the sponge. Cloaca central, cylindrical, nearly as long as_ the sponge, armed internally with spiculated, equiangular, triradiate spicula; spicular ray ensiform, very long ; mouth of cloaca simple, unarmed. Oscula simple, slightly depressed, as numerous as the interstitial cells. Pores inconspicuous. Skeleton spicula equi- angular triradiate. Colour.—Cream white. Habitat Guernsey, Mrs. Buckland. Examined.—In the dried state. T am indebted to my kind friend the late Mrs. Buckland for this new and interesting species. She found it at Guernsey, between high- and low-water marks, parasitical on Corallina oficinalis. It is in size, form, and colour, so much like Grantia ciliata that a superficial observer would very pro- bably mistake it for that species. Of four specimens in my possession, the largest is seven lines in length and two lines at its greatest diameter, the smallest is three lines in length and not quite two in diameter. All the specimens are sessile, the base of the sponge embracing the stem of the Coral- lina firmly. The defensive spicular rays arming the inte- rior of the cloaca are remarkably long ; the ray progres- sively increases in size from its insertion at the centre of the triradiate .spiculum for about three fourths of its length, and then gradually attenuates to its distal extre- - mity, where it terminates acutely, so that its outline is very like that of an ancient sword. . They are all of them more or less inclined towards the mouth of the cloaca, and their abundance and efficiency 26 A MONOGRAPH OF THE render the arming of that part of the sponge unneces- sary. ‘The spicular ray is much stouter and longer than the rays of the spiculum on which it is based. ‘The external surface of the sponge is strengthened and supported most effectually by numerous very large, stout, fusiformi-acerate spicula, which are all disposed in the direction of its long axis ; they are readily to be seen by the aid of a lens of an inch focus. 4. GRANTIA TESSELLATA, Bowerbank. Sponge. Elongately oval, sessile; surface even, tessel- lated, densely hispid. Cloaca central, cylindrical, nearly as long as the sponge; armed internally with spiculated, equiangular, triradiate spicula; spicular ray ensiform, short, stout, and curved. Mouth of cloaca armed with a thick ciliary fringe of long, mgid, acerate spicula. Base of the ciliary fringe strength- ened with numerous rectangulated triradiate spicula, with the coincident radii disposed at right angles to the ciliary spicula, and the third ray directed towards their bases. Oscula simple, slightly depressed, as numerous as the interstitial cells. Pores inconspi- cuous. Interstitial cells: distal terminations obtuse ; furnished each one with a dense corymboid fasciculus of short acerate spicula. Skeleton spicula equi- angulated and rectangulated triradiate ; radii attenu- ating, stout. Colour.—Brown. Habitat.—Guliot caves, Sark, Mrs. Buckland; off Fermain Bay, Guernsey, 13 fathoms, Rev. A. M. Norman. Ewamined.—In the dried state. I am indebted to my kind friend the late Mrs. Buck- land, an able and enthusiastic zoologist, for this new and interesting species of Grantia. BRITISH SPONGIADA. 27 In form and size it is very like G. ciliata, but the colour and the strikingly tessellated character of its surface at once distinguishes it from that species. The tessellated appearance is produced by the corymboid fasciculi of short acerate spicula, which are based one on the centre of each of the distal ends of the interstitial cells, and the spicula of which diverge slightly from each other until, meeting the apices of the adjoining fasciculi, they mutually compress each other into four-sided figures; but although these bundles present so dense an aspect at their distal termina- tions, there appears always a free space around each of their proximal ones, by the means of which free access to the external water is afforded to the pores after all large extraneous matter has been separated by the distal termi- nations of the fasciculi. The difference that exists in the defences of the porous systems of this species and that of Grantia ciliata 1s very remarkable and interesting. The same end is attained in each, but by completely opposite contrivances. The internal defences of the cloaca are remarkably stout and abundant. The external defensive organ also, although apparently like that of G. cddiata, differs from it in structure in several essential points. Thus, in G. ciliata the ciliary spicula around the mouth of the cloaca are remarkably long, slender, and flexible, and are, therefore, supported at their bases by short but very strong acerate spicula ; while in G. tessellata we find the ciliary spicula stouter and very much more rigid than in the kindred species, and there is, accordingly, a total absence of the large acerate subsidiary spicula; but as some support of the proximal ends of the ciliary spicula appears to be still necessary, we have them bound together at their bases, for about one third or one fourth of their length, by a beautiful regular interlacement of rectangulated triradiate spicula. Again, the same end being attained in each species by an admirable variety of construction. The whole of the spicula of this sponge are stouter in their proportions than those of G. ciliata. I have seen but two specimens of this species ; they are both of about 28 A MONOGRAPH OF THE the same size and proportions, and not exceeding five lines in length and a line and a half in diameter. Genus—Levucosourenta, Bowerbank. 1. Leucosolenia botryoides, Bowerbank. 2. — contorta, Bowerbank. 3. —_— lacunosa, Bowerbank. A, — coriacea, Bowerbank. fd 1. Levcosotenta Borryoipes, Bowerbank. GRANTIA BOTRYOIDES, Fleming. _— _— Johnston. SPoneia _— Ellis and Solander. Sponge. Arborescent, cylindrical, slightly pedicelled ; parietes very thin; surface smooth. Cloaca very large, armed internally with spiculated equiangular triradiate spicula; spicular ray large and long, slightly curved; mouths of cloaca one or more, terminal, simple, and unarmed. Oscula and pores inconspicu- ous. Spicula of skeleton equiangular, triradiate ; radii somewhat short and stout, rapidly attenuating. Colour.—White. Habitat.—Parasitical on fuci and zoophites, coasts of Great Britain, abundantly, littoral and to 8 or 10 fathoms. Exramined.—Alive. I have found this species abundant in eight or ten fathoms at Weymouth Bay, ''enby, Torbay, and in many other localities where I have dredged, and it is usually para- sitical on small fuci, along with Grantia compressa and ciliata. When placed in a cell in a little somewhat turbid sea water, a a power of ye linear, the excurrent streams are generally seen pouring forth strong i the eneis ‘ the Tiecs Renee Tufts of this species are frequently found exceeding ani BRITISH SPONGIADA. 29 inch in diameter ; and if these be carefully examined they will be found to consist of numerous individuals congre- -gated together, and not of one complex sponge, as at first sight they might readily be thought to be. In the young state they appear as short unbranched cylinders, or with a single terminal branch; others have two, three, or more short branches, each usually having a terminal cloacal mouth, but it is rather unusual to find them as much branched as the specimens represented by Ellis and Dr. Johnston. However much branched, there is never but one cloacal cavity, which extends throughout the whole of the sponge. The defensive radii within the cloaca are numerous, and many of them as long as nearly half the diameter of that organ, and they are slightly curved near the points in the direction of its mouth. ‘The pores may be seen in dried specimens when viewed with a power of about 150 linear by direct light ; but when the interior sur- face is examined, either by direct light or when mounted in Canada balsam by transmitted light, it is very difficult to detect any regular orifice in the form of an osculum. The spicula of the skeleton,as compared with thoseof Leucosolenia contorta, the only known British species with which this sponge is liable to be confounded, are comparatively short and stout, and their radii, unlike those of Z. contorta, decrease rapidly in diameter from the base to the apex. Ellis’s figure of the spicula of Spongia botryoides is very correct. 29. LeucosoLenia contorta, Bowerbank. Sponge. Sessile, a mass of contorted anastomosing fistulze ; parietes thin; surface smooth, with a few procumbent acerate spicula. Cloaca very large, continuous, armed internally with spiculated, equiangular, triradiate spicula; spicular ray short, stout, slightly curved ; mouths numerous, simple, and unarmed. Oscula and pores inconspicuous. Spicula of skeleton equiangular 30 A MONOGRAPH OF THE triradiate; radii long and slender, attenuating very gradually. Colour.—W hite. Habitat.—Guernsey, Mrs. Buckland; Scarborough? Mr. Bean; Guliot Caves, Sark, J. S. Bowerbank. Examined.—In the dried state. I am indebted to my kind friend the late Mrs. Buckland for twenty-eight specimens of this little species. The largest does not exceed half an inch in length, a quarter of an inch in breadth, and about two and a half lines in thick- ness, and the attachment rather exceeds a quarter of an inch in diameter. The smallest specimen is about one line in length and half a line in breadth. The whole of the specimens are either coating in habit or have very broad basal attachments, or, if seated on. a fine branching fucus, instead of being partially pedicelled after the habit of L. botryoides, it appears always to embrace and envelop the small branches of the fucus in its neighbourhood. The spaces between the inosculating fistulz seldom exceed one and a half time the diameter of those tubes, and are fre- quently not more than half their diameter in width, and all the specimens in my possession are uniform in their structure in this respect. The mouths of the cloaca are numerous, and are usually at the termination of short lobular projections of the sponge. The spicular ray of the imternal defensive spicula are very much shorter in proportion than those of LZ. dotryoides, rarely exceeding one fourth or one fifth of the interior diameter. From these and other general differences in character from the ordinary arborescent forms of Z. dotryoides, I was at first induced to believe that this sponge might probably prove to be Spongia complicata of Montagu; but Montagu’s figure in plate ix, vol. ii, of the ‘Transactions of the Wernerian Society,’ does not represent the contorted character of our sponge, while it is really a very charac- teristic figure of Spongia botryoides of Ellis and Solander, BRITISH SPONGIAD. 3l or Grantia botryoides of Fleming (‘British Animals,’ p. 525). Montagu also states that the spicula of Z. botryoides are more than four times as large as those of his 8. complicata, while the spicula of the species under consideration are not quite so stout at the bases of the radii, but are very much larger than those of Grantia botryoides of Fleming, and that author, who sent the specimens to Montagu, repudiates his species. Dr. Grant, who also treats of 8. complicata of Montagu in his paper “ On the Structure of some Calcareous Sponges,’ * likewise received his specimens from Dr. Fleming. Dr. Johnston, also, with good reasons for his conclusion, rejects Montagu’s species as but a variety of S. botryoides. Under these circumstances I think it is better to reject the term complicata, and to adopt that of contorta for the species under consideration. The form of this sponge is so distinctly different from that of Z. botryoides that, with the assistance of a lens of two inches’ focus, it cannot be well mistaken for that species, which, although they are frequently congregated in groups, have not apparently the habit of uniting together in one mass by inosculation, while Z. contorta always appears to consist of a mass of contorted inosculated fistule. Besides this variation in external form, there is a distinct difference existing between the skeleton spicula of the two species, for, although both are equiangular triradiate, their proportions are very different from each other, those of ZL. botryoides being proportionally much stouter and having much shorter radii than those of Z. contorta. The rays of the former also attenuate rapidly and regularly from base to apex, while those of the latter retain nearly the same diameter, or are attenuated very gradually until near the apices, and are then more suddenly acuminated, so that when the eye has become familiarised with the two the species may be readily decided by the forms of the spicula only. The external surface of Z. contorta is also sparingly furnished with recumbent acerate spicula, mostly disposed in a longi- tudinal direction, and I have never observed like spicula on the surface of Z. botryoides. * «Edinb. Med. Phil Journ.,’ i, 169. 32 A MONOGRAPH OF THE In the dried condition Z. contorta and coriacea are more liable to be mistaken for each other than the former and L. botryoides, but the total absence of defensive spicula on the cloacal cavity of Z. coriacea readily distinguishes it from either of the other two species. 3. LeucosoLENnta LAacuNnosa, Bowerbank.’ GRANTIA LacuUNOSA, Johnston. Sponge. Massive, more or less elliptical, pedicelled ; surface smooth ; fistule tortuous. Cloaca unarmed internally; mouth simple, single, and unarmed. Pores inconspicuous. Skeleton: spicula equiangular triradiate; radii very slightly attenuated until near the apices, termination rather obtuse, and a few long acerate spicula near the base of the sponge. Colour.—Light gray or white. Habitat-—On rocks at low water near Scarborough, very rare, Mr. Bean ; in deep water, coast of Treland, Mr. Hyndman ; Shetland, Mr. C. W. Peach. Examined.—lIn both the fresh and the dried state. The specimen of this sponge figured and described by Dr. Johnston in his ‘ History of British Sponges,’ p. 176, has the body of the sponge five lines in height and two in breadth, while a dried specimen in my possession, for which I am indebted tc my friend Mr. Bean, has the same part two and a half lines-in height and four in breadth, the proportions in this case being nearly reversed; the pedicel in both is nearly of the same height. Dr. Johnston describes the species as “flabellate, entire or undivided, white, greatly compressed, the sides perforated with numerous irregularly elliptical holes or vents, so as to give a lacunose appearance to the dried specimen; structure compact, friable when dry; spicula all triradiate. The remarkable character afforded by the numerous large holes in the sides, BRITISH SPONGIADA. 33 so unlike the fecal orifices of the other species, distinguishes this at once, and removes the suspicion of its being a variety of any other.” Nearly the whole of the above description is incorrect, the errors arising from the description having been made from a dried and artificially compressed specimen. I have been more fortunate in this respect than my late friend the author of the ‘ History of the British Sponges,’ having been kindly presented with a specimen dredged in deep water and preserved in spirit, in September, 1858, by my friend Mr. George Hyndman, of Belfast. This beautiful little specimen is based in a depression on a small fragment of stone, the whole sponge being about six lines in height, three les consisting of a curved pedicel of nearly uniform size, having a diameter of about one third of a line, and the remainder of the body of the sponge assumes the form of a regular ellipse, the greatest diameter of which is about a line and a half. The body consists of numerous fistulz, which spring from the apex of the solid pedicel and assume a longitudinal direction, frequently anastomosing with each other in their progress towards the distal extremity of the body of the sponge. A portion of the fistule of the interior discharge their contents into a central cloacal cavity, which is somewhat irregular in form, and gradually increases in its diameter from its origin at the proximal end of the body until it reaches nearly its distal termination, where it expands into a large irregularly conical cavity, into the base of which the longitudinal fistule of the surface dis- charge themselves, and at the apex of the cone and of the body of the sponge there is a single circular mouth to the cloaca of about the same diameter as that of one of the fistule of the sponge. I sliced off a portion of a dried Specimen of the sponge in a longitudinal direction, and thereby obtained a view of a portion of the cloaca, but I could not detect the slightest indication of internal armature in that organ, nor could I in any part of the sponge find a single spiculated triradiate spiculum. Nor is there any indication of external defensive spicula at the mouth of the cloaca. The whole of the surface of the interior of the 3 34 A MONOGRAPH OF THE fistula and central cloacal cavity is abundantly furnished with circular nucleated cells varying in diameter from sth inch to ;é;th inch; they are regularly dispersed, and are seldom more than about the length of their own diameter distant from each other. The nuclei occupy from one third to about two thirds of the diameter of the interior of the cell, and neither in it nor in the cell surrounding it is there any appearance of granules. I could not detect any of these cells in the dried specimen of the same species for which I am indebted to my friend Mr. Bean, nor have I ever seen similar cells in any other calcareous sponge. It is difficult in the present limited state of our knowledge of this tribe of sponges to determine the office of these bodies in the economy of the sponge, but it is most probable that they are the reproductive organs. 4. LEUCOSOLENTA CoRIACEA, Bowerbank. GRANTIA CORIACEA, Fleming. = _ Johuston. Sponge. Sessile incrusting; fistule tortuous, anasto- mosing ; surface smooth, parieties thin. Cloacal cavity continuous, unarmed internally ; mouths incon- spicuous. Oscula and pores inconspicuous. Spicula of skeleton equiangular triradiate, radii thick, apices obtusely pointed. . Colour.—Dark crimson, Mrs. Buckland; dirty bluish gray or white, Johnston ; lemon yellow, Rev. A. M. Norman ; deep nut brown, J. S. Bowerbank. fabitat—Scarborough, Mr. Bean; Peterhead, Mr. Peach ; Guernsey, Mrs. Buckland; Berwick Bay, Johnston ; Guliot Cave, J. S. Bowerbank; Burra-Firth Cave, Rev. A. M. Norman. . I found this sponge by the aid of my friend Mr. Bean of Scarborough, and I have also received it from him in the BRITISH SPONGIADA. 35 dried state. In both cases it was closely attached to and coating the piece of rock on which it was seated. Mrs. Buckland found it at Guernsey. On a small slip of paper accompanying the specimen she has written: “ What are these Grantias, some are dark crimson when living on sponges at low water?’ Examined by the microscope in a little water these specimens exhibit an abundance of red sarcode. Dr. Johnston describes them as of a “dirty bluish gray or white when recent.” The specimens I found myself were of a dark brown colour. It would appear therefore that this species varies considerably in that character. The body of the sponge is composed of tortuous fistulae anas- tomosing in every direction, the spaces between them being usually very much less than the diameter of the fistule themselves. The parieties. of the sponge are thin and the surface smooth, and I have never found more than one form of spicula in any part, the equiangular triradiate ones of the skeleton; these spicula are very much like those of L. contorta in size and proportion, but the radii are more obtusely terminated than in that species. The cloacal cavity is continuous and totally without defensive spicula, and by this character the species may always be distinguished from Z. con/orta. Dr. Johnston in treating of this sponge says, ‘“ There are no fecal orifices.”” I have carefully examined a considerable number of specimens with a microscopic power of 160, but have been unable to detect any of the mouths of the cloaca, and attribute this failure to the habit of the animal: of closing those orifices at the approach of danger, or while in a state of inaction, and the total absence of internal defensive spicula, would seem to indicate the existence of such a power for its protection from its enemies. In ZL. contorta the mouths of the cloaca are at the distal ends of tuberous projections of the sponge, some of these appear fully open, others with a very small orifice apparent, while others are entirely closed, and in this condition no arrange- ment of the skeleton spicula different from that of other parts of the sponge is apparent that would indicate the place of the mouth of the cloaca; and this may very 36 A MONOGRAPH OF THE probably be also the case in Z. coriacea, which in the structure of its parieties very closely resembles those of LL. contorta. Montagu’s description of his Spongia cortacea applies very much more correctly to a small specimen of Raphyrus Grofithsii of this work than to the calcareous species de- scribed above. This sponge has been found as far north as Davis's Straits by Dr. Walker, who presented a specimen of it to Professor Dickie of Queen’s College, Belfast, from whom I received it for examination in the autumn of 1858. The specimen differed in no respect from those which I have received from Guernsey. Genus—Leuconta, Grant. 1. Leuconia nivea, Bowerbank. 2. — fistulosa, Bowerbank. 3. — pumila, Bowerbank. 1. Levoonra NivEA, Bowerbank. Grantia Nivea, Fleming. —_ — Jdokaston. Sponge. Sessile, massive or coating; surface lobular or crested, smooth. Cloacee numerous, mouths simple, armed internally with very large and stout equiangular spiculated triradiate spicula, radii attenuated. Mem- brane of cloaca furnished abundantly with unicurvo- cruciform spicula. Oscula numerous, simple, dis- persed over the surfaces of the cloacee. Pores minute. Spicula of skeleton equiangular trjradiate, very variable in size and stoutness. Spicula of interstitial and dermal membrane small, acerate; and minute attenuato- spiculated triradiate spicula; spicular ray short, basal rays tripodate. BRITISH SPONGIADZ. 37 Colour.— White. f Habitat.—Scarborough, Mr. Bean ; Guernsey and Sark, Mrs. Buckland, and J. S. Bowerbank. Examined.—In the dried state. * The specimens of this sponge, which I have received from my friend Mr. Bean, of Scarborough, are thin, with sinuous crests running over the surface, on the highest part of which are the mouths of the cloace. Those from my late friend Mrs. Buckland, and also those I have found, were from the Guliot Caves, Sark, and other localities in the Channel Islands; these specimens are more massive, and the surface is furnished with from one to seven or eight conical lobes, each terminated by the mouth of a cloaca. The cloace are separate and distinct organs, at the base of each there is usually the terminations of one or more large excurrent canals; and on all parts of the walls of the cloaca there are numerous dispersed oscula. The defensive spicula of the parieties of the cloacae are remark- able, and disproportionately large. The equiangular tri- radiate bases are buried deep in the interstitial tissues, while the spicular rays passing through the walls of the cloaca project for about half or two thirds their length into its cavity, presenting a formidable array of wéapons to greet any intruder, while the basal radii perform an im- portant part in strengthening the skeleton. The basal radii of some are nearly approaching to the rectangular form, but the normal form is equiangular. The unicurvo-cruciform spicula abound on the membranes lining the cloace of the sponge. Their axial radii are dis- posed very nearly in the direction of the long axis of those organs, and the curves formed by the lunate’ radii always have their points towards the mouth of the cloaca. ‘They are always lying on one of their flat sides, and when undis- turbed I have never seen any one of the radii projected out of the plane of the membrane on which they are re- posing. The apical ray often projects for the whole of its length over the margin of the terminal orifices of the imter- stitial excurrent canals, so as to appear to perform the 38 A MONOGRAPH OF THE office of a defensive spiculum, but as we find no similar projection of defensive spicula on the opposite side of these terminal orifices, it is evident that this position is accidental rather than premeditated. I could not find any of these spicula on the interstitial membranes of the sponge, between the lining membrane of the cloaca and the dermal mem- brane. The pores are minute and are best seen by direct light with a power of about 160 linear. They are situated in the areas of the dermal membrane, which are formed by the network of equiangular triradiate spicula, by which it is supported; every area has not a pore; but sometimes one large area will have two or three, but one is the more usual number. The triradiate spicula of the skeleton are very variable in size and strength; some of them are quite as large as the triradiate bases of the large defensive spicula of the cloaca, and these are placed along with the basal portions of those spicula, about midway between the dermal mem- brane and the parieties of the cloaca; while the rest of the skeleton spicula do not exceed in size the ordinary dimen- sions of those of the whole tribe of such sponges. The dermal and interstitial membranes abound in small acerate tension spicula, and with minute, attenuated, spicu- lated triradiate ones. ‘The spicular ray rarely exceeds in length a third or a fourth of the length of one of the basal radii, and the basal rays are not, as it is usually the case, in the same plane, but are projected backward in an equal degree, forming, as it were, a tripod support to the spicu- lar ray. The sponge does not appear to attain a greater size than about one and a half or two inches in diameter; the speci- mens from Sark and Guernsey are smaller than those from Scarborough in diameter, but very much more lobular and elevated. BRITISH SPONGIAD. 39 2. Leuconia FistuLosa, Bowerbank. GRANTIA FISTULOSA, Johnston. Sponge. Fistular, sessile; surface hispid, with large, stout, fusiformi-acerate spicula. Cloaca single, central, cylindrical, nearly as long as the sponge; armed in- ternally with spiculated equiangular triradiate spicula ; spicular ray attenuated ; mouth of cloaca simple or very slightly fringed with short, slender, acerate spi- cula. Oscula simple, numerous, disposed irregularly over the surface of cloaca. Pores inconspicuous. Skeleton spicula. Large, stout, fusiformi-acerate ; equiangular triradiate, radii attenuated, long, and slender; and slender rectangular triradiate spicula ; coincident radii very long, angulating ray very short. Colour.—Pure white alive ; cream white dried. Habitat—Plymouth, Mr. John Howard Stewart; off Saint’s Bay, Guernsey, Rev. A. M. Norman. Examined.—In the dried state. I am indebted to my late friend Mr. John Howard Stewart of the Royal College of Surgeons, for the loan of two specimens of this sponge. He found them on the rocks of the Eddystone Light House at low water. The largest one is two inches in length, and seven lines in width, at about one third its height from the base. It is somewhat compressed, and is irregular in form, one side being straight, while the other is sinuously curved. The other specimen is one inch and a quarter long, nearly cylindrical in form, but curved to about the fifth part of a circle. I have also a specimen that was presented to me many years ago by my late friend Professor Edward Forbes, who could not recollect the locality. It is two inches and two lines long, four lines at its greatest diameter; is nearly cylindrical and is curved into a slightly sigmoid figure. 40 A MONOGRAPH OF THE From the description given by Dr. Johnston, in page 181 of his ‘ History of British Sponges,’ of Grantia fistu- Josa, there is little room to doubt that the sponge sent to him by Mr. William Thompson, and those found by my friends Mr. Stewart and Professor Forbes are of the same species; but from the structure of the latter specimens, it is quite certain that they cannot be considered as Grantias according to the structural limitations of that genus. In Mr. Stewart’s and Professor Forbes’s sponges, there is not the slightest indication of the large, regular, intersti- tial cells that radiate from the central axis of the sponge in G. ciliata or compressa; although there is a large cen- tral cloaca as in those species. On the contrary, the whole of the walls of the animal closely resemble a halichondra- ceous sponge in structure, and is permeated as in that tribe by numerous contorted canals, the excurrent orifices of which are at the inner surface of the sponge; which forms one great cloacal cavity as in the true Grantias. I have, there- fore, referred these sponges to the new genus Leuconia. The spicula with which the external surface is armed are very stout and strong, but not so very numerous; they are similar in size and strength to the large fusiformi- acerate ones, which are recumbent, principally in a longitu- dinal direction at the surface of the sponge, but the defen- sive ones are considerably longer of the two. The principal part of the skeleton is constructed of the slender equiangular triradiate spicula, and the rectangular triradiate ones are found more especially at the outer sur- face, and also near the mouth of the cloaca, where they are disposed with the long coincident radii most frequently at right angles to the long axis of the sponge, and the angu- lating ray pomting backwards, thus forming a strong but light and elastic interlacing structure. The cloaca is very capacious and abundantly armed with spiculated equiangular triradiate spicula ; the spicular ray being long, slender, and gradually attenuating, and they are all slightly curved-in the direction of the mouth of the cloaca. The slender acerate spicula forming the very meager BRITISH SPONGIADA. 4] _ ciliary defensive sponge, are very short and few in number. The pores in Professor Forbes’s sponge are barely visible with the aid of a two inch lens. The oscula are very nu- merous and minute, but they are visible to the unassisted eye in dried specimens. From the difference in the form and size of the speci- mens under consideration, it would appear that this species is subject to’ much variation in both of these characters. Since the above was written, my friend the Rev. A. M. Norman has taken fourteen specimens of this sponge off Saint’s Bay, Guernsey, in 1865, several of them rather exceeded two inches in length, and three of them did not exceed seven lines in length, with a proportionate decrease of diameter, the others were intermediate between the two extremes ; in every other respect they agreed perfectly with the two specimens previously described. 3. Leuconia pumILA, Bowerbank. Sponge. Sessile, elongo-oval, surface smooth; oscula simple, on the parieties of the central elongated cylindrical cloaca. Internal defensive spicula, spicu- lated, equi-angular, or rectangular triradiate spicula ; spicular ray short, attenuated. Cloaca cylindrical, extending from the base to the distal end of the sponge, mouth simple, membranous, thin. Pores in- conspicuous. Sketeton spicula equi-angular, trira- diate, very large and strong, variable in their propor- tions. Interstitial membranes. Spicula equi-angular, triradiate, small and slender. Colour. —Cream white, alive and dried. Habitat.—Guernsey, Rev. A. M. Norman. Examined.—in the dried state. Four specimens of this sponge were obtained by the Rev. A. M. Norman while dredging in company with Mr. Jeffreys, off Guernsey. ‘The largest does not exceed 4:2 A MONOGRAPH OF THE eight lines in length, by not quite two lines in greatest diameter, and the smallest measured four lines in length, and one, greatest diameter. The form and general aspect of the sponge is very like that of a young specimen of L. fistulosa, but the total absence of hispidation, and the very large size of the surface spicula renders them readily separable by the aid of a lens of two inches focus. The surface as well as the whole substance of the sponge is formed by a strong interlacing of exceedingly large trira- diate spicula, the space covered by many of them being quite equal to half the greatest diameter of the sponge. These spicula vary to a considerable extent in their propor- tions, apparently in accordance with the necessities of their sifuation, and at the surface they frequently have one ray much longer than either of the other two, and in this case the elongated ray usually runs in the direction of the long axis of the sponge; besides these large and strong spicula, there is no indication of surface armature. The internal defensive spicula are not very numerous; the spicular ray is equally attenuated, and usually not more than about half the length of either of the others. The mouth of the cloaca is composed of a thin membrane strengthened and supported by slender rectangulated tn- radiate spicula, the margin being nearly purely mem- branous. ‘The interstitial membranes are abundantly fur- nished with small equiangular triradiate tension spicula, disposed without any appearance of regularity. Genus—Lurvucocypsia, Bowerbank. 1. Leucocypsta Gossett, Bowerbank. Sponge. Massive, sessile; surface smooth; oscula ter- minal, slightly fistulose. Pores inconspicuous. Dermal membrane pellucid, furnished with a minute, irregular reticulation of small equianguylar triradiate spicula, with BRITISH SPONGIADS. 43 attenuated radii. Skeleton, interstitial cavities rather large, irregular in form. Excurrent canals large, rather numerous, congregated near the middle of the sponge ; their parieties abundantly armed with stout, spiculated, equiangulated triradiate defensive spicula; spicular ray large and stout; and also with slender rectangu- lated triradiate and spiculated rectangulated triradiate spicula ; rectangulating rays short and slender. Spi- cula of the skeleton equiangulated, attenuated, trira- diate, large and stout; and a few very large and stout fusiformi-acerate spicula. Interstitial membranes pellucid, aspiculous. * Colour —Cream white. Habitat.—Torquay, Mr. Gosse; Guliot Caves, Sark, J. S. Bowerbank. Examined.—In the dried state. I am indebted to my friend Mr. Gosse for having called my attention to the differences in external characters of this species and similar sized specimens of Leuconia nivea. A slight microscopical examination of the specimens he sent me, sufficed to convince me that they were not only different as species, but that they were also members of a different genus, being the only British representative of the genus Leucogypsia; and on examining a considerable number of specimens of Leuconia nivea that I had collected from the Guliot Caves in Sark, I found among them four fine specimens of Mr. Gosse’s sponge which I had over- looked amidst the abundant spoil of those prolific caves. The form of Leucogypsia Gossei is massive, with a ten- dency to elongate upward in the larger specimens, which sometimes attain the height of an inch and a half, and at the distal extremity the oscula are usually found, some- times as simple orifices, and at others as slightly elevated simple tubes, about half the height of their own diameter. The colour and variable form and size of these sponges renders them very liable to be confounded with Leuconta nivea by a hasty observer. The spicula of the dermal 44 A MONOGRAPH OF THE reticulation are very small in comparison with those of the skeleton, their spread being not more than about one fourth part that of the latter, and the radii are slender and deli- cate in proportion to their diminished size. The interstices of the network are small in proportion, about equal in their area, but irregular in their form. The excurrent canals are variable in size, but usually rather large, and they are irregularly congregated about the middle of the sponge. They originate near its base, and gradually increase in diameter as they progress in nearly straight lines to its distal extremity ; occasionally, but rarely, a canal may be observed to emerge in a lateral direction. The parieties of these canals are amply provided with defensive spicula; they are of three descriptions. The normal form is that of a stout equiangular spiculated triradiate spiculum ; the spicular ray is not so long as either of the other rays, but is stout and usually slightly curved towards the oscular orifice. ‘The other two forms may be considered as sub- sidiary defences ; they are spiculated rectangular triradiate, aud simple rectangular triradiate; the rectangulating ray in both is very short, usually not exceeding about one fourth the length of either of the other rays. ‘The defen- sive organ in the first of these two forms is the spicular ray ; in the second, it is the short angulating ray of the spiculum, the two long rays being usually disposed in a line with the long axis of the canal, while the short angu- lating ray is projected at about right angles to the surface of the canal; both these forms are much more slender than the equiangular defensive spicula, which are of about the same ‘size as those of the skeleton. Immediately beneath the surface of the sponge there are very large fusiformi-acerate spicula disposed singly at nearly equal distances from each other, and in lines at right angles to the surface. ‘heir diameter is three or four times that of the largest sized skeleton spiculum, and their length at least twice as great as the space embraced between any two of their angulating radii. Their distal apices do not appear to pass through the dermal membrane, but are usually slightly below it. A few of these large spicula BRITISH SPONGIADA. 45 are found more deeply imbedded in the sponge; they may, therefore, be considered rather as subsidiary skeleton spicula than defensive ones. The interstitial membranes are abun- dantly present, they are thin and pellucid, and do not present the slightest indications of tension spicula. Orver IT.—SILICEA. Genus.—Gropia, Lamarck. Greopia ZetLanpica, Johnston, ALCYONIUM CYDONIUM, Jameson. Wern. Mem., i, 563. Cyponrum Muuieni, Fleming. Brit. Animals, p. 516. Sponge. Massive, sessile ; surface even, strongly hirsute, with large fusiformi-acerate and fusiformi-acuate spi- cula projected at right angles to its plane. Dermal membrane thin, translucent, spiculous, spicula atte- nuato-stellate, abundant. Connecting spicula attenuato- patento-ternate, stout ; and attenuato-recurvo-ternate, long, and slender, with rarely, slender porrecto-ternate spicula. Oscula dispersed, or occasionally congregated. Pores inconspicuous, minute, dispersed. Skeleton spicula fusiformi-acerate, large. Spicula of the inter- stitial membranes attenuato-stellate, variable in size ; and also acerate, small, and slender. Gemmules globose, slightly depressed. Habitat—Island of Fulah and Unst. Jameson. Cape of Good Hope? Fleming. Colour.—Cream yellow. Examined.—%n the dried state. The first record of this species is in Dr. Jameson’s list of Scottish vermes, ‘Memoirs of the Werncrian Nat. Hist. 46 A MONOGRAPH OF THE Society,’ vol. i, p. 563, where, under the head of Alcy- onium, it is simply recorded as “A. cydonium, Island of Fulah and Unst.” Dr. Fleming, in his ‘ History of British Animals, p. 517, has described the sponge, and has changed the specific name into a generic one, and given it a new specific one, designating it Cydontum Mulleri. Dr. Johnston, in his ‘ History of British Sponges,’ has correctly referred the sponge to Lamarck’s previously established genus Gecdia (‘ Anim. S. Vert.,’ 2nd edit., i, p. 593), but has changed the specific name to Zetlandica, apparently from being satisfied that Muller’s A/cyonium cydonium was really 4. digitatum:of Ray and Linneus. I am much indebted to Dr. Fleming for kindly sending me the type specimen for examination. It is an irregular, tuberous mass, the greatest diameter of which is two and a half inches, with several large and deep depressions, one of which is an inch across, and three fourths of an inch in depth, forming, when it stands on the cut base, a deep arched cavern in its substance. On each side, near the base of the walls of the cavern, there is a single large osculum, the eighth of an inch in diameter, and one of them has the membrane closing it ‘remaining in a partial state of contraction, protruding, and exhibiting a central orifice about one sixth of a line in diameter, and near the greater one there is an irregular group of smaller oscula, and a few others, similar to the latter, are visible in the other depressed portions of the sponge. The true base of the sponge has been destroyed. In some of the natural depressions on the surface of the sponge there are the remains of large fusiformi-acuate spicula, those protected portions of the surface having evidently been quite hirsute with them. The upper portion of the specimen is thickly studded with minute stellate depressions or pits ; this pitting of the sur- face is caused by the contraction and depression of the dermal membrane, immediately above the distal orifices of the intermarginal cavities. Dr. Johnston says of the-crust that it is “dimpled in some places with numerous pores placed pretty closely together, and large enough to be visible with the naked eye.” These orifices are not the pores, but BRITISH SPONGIADA. 47, they are the intermarginal cavities which receive the minute streams from numerous pores situated immediately above and within a short distance of them; the true pores per- forating the dermal membrane are too minute to be visible without the assistance of considerable microscopic power. In the dried specimens these “ dimpled” depressions of Dr. Johnston, or stellate orifices of Dr. Fleming, have the appearance of forming a well-marked character of the sur- face, while, in truth, I believe they are not visible on the surface of the sponge in its natural condition before it is dried ; at least this is the case with G. Barre/tii. In the dried specimen they are apparent, but not in the slightest degree visible in any part of the same specimen that was pre- served in salt and water while fresh from the sea; we may therefore reasonably conclude, that they do not form a character applicable to the description of the species. In the present condition of the sponge the villous cha- racter described by Dr. Fleming is not in the slightest degree apparent, excepting in the depressed parts before mentioned, but if we examine a section of the sponge at right angles to its surface, we find that remains of large spicula passing entirely through the crustular dermis are abundant ; they originate at a short distance beneath the inner surface, pass through the crustular mass, and project at least half their length beyond its outer surface. In its natural condition it would therefore be decidedly hirsute. There are also a few small acerate spicula at right angles to the surface, but these rarely project beyond the dermal membrane, and are not sufficiently long to reach the inner surface of the crust. Whiere there are any remains of the dermal membrane it is profusely furnished with attenuato-stellate spicula, the same as those of the sarcode, but its dilapidated condition afforded very unsatisfactory information regarding the pores; apparently they are equally dispersed over its surface. The connecting spicula are of two distinct forms, and are very large and long. The attenuato-expando-ternate ones are very stout and strong; the triradiate heads of this form are generally. parallel to each other at the base of the 48 A MONOGRAPH OF THE crustular dermis, and are slightly imbedded in its substance, while the attenuato-recurvo-ternate ones are less regularly disposed. The heads of some of these are intermixed with those of the expando-ternate ones at the inner surface, but a considerable number of them project their triple hooks deep into the substance of the crustular dermis, and occa- sionally almost reach the outer surface. ‘The shaft of this form of spiculum is very slender compared with its length, which is greater than that of the expando-ternate ones, while the diameter is not above one fourth that of the latter; the shaft is also frequently flexuous. Occasionally, but very rarely, we find a specimen of porrecto-ternate spiculum mingled with the recurvo-ternate ones. ‘The fusiformi- acerate spicula of the skeleton are large and strong; their greatest diameter is not quite so much as that of the expando-ternate ones. The interstitial membranes are very abundant, they are of uniform texture, and, when free from sarcode, very pellucid. The type specimen has the mem- branes abundantly coated with sarcode, amidst which are numerous small, lentiform cells, ;4,th of an inch in diameter. I did not detect these bodies in a specimen in my pos- session in which the sarcode is not nearly so abundant, probably from its having been cleaned by soaking in fresh water. The attenuato-stellate spicula of the sarcode are abundantly dispersed over the membranes ; they are very variable in size, some not exceeding, from point to point of the rays, sdsth of an inch, while others attain an extreme diameter of ith of an inch; the radii of the largest of them, beneath a linear power of 660, exhibited a tendency to be incipiently spinous. The gemmules are uniformly globose ; an average sized one measured ,{,rd of an inch in diameter. I did not observe any of them in a young and productive state in the crustular dermis, but in those which were im- bedded near the centre of the substance of my own specimen - there were a considerable number in the young state having the opaque nucleus in the centre. This specimen I obtained from Mr. James de C. Sowerby; he has no recollection of its history, but says he had various specimens, many years since, from a man who used to collect for Colonel Montagu. BRITISH SPONGIADA. 49 As I received at the same time a specimen of Zethea lyn- curium, and the type specimen of Spongia pulchella, Johnston, described in the ‘ British Miscellany,’ it is very probable that Mr. Sowerby had it from the man to whom he alludes, and that its locality was probably either Shetland or the Orkney Islands. It has the form of rather less than half of a depressed turnip. ‘The section is two and three quarter inches in length and one and a half in height, and from the flat section to the furthest part of the opposite curve it measures one inch. It agrees completely in its organic characters with the type specimen. When Dr. Fleming favoured me by sending to me the type specimen of his Cydonium Mulleri, he sent with it two other specimens ; one of them is labelled, “ From the Island of Dominica, in the West Indies,” and proved to be Geodia gibberosa, of Lamarck; the other was labelled, “From the Cape of Good Hope.” In this specimen I have been unable to discover such organic difference as to entitle it to be considered distinct from G. Zetlandica. It is two and a half inches long, two inches broad, and one inch in height. The dermal membrane is entirely destroyed by washing or maceration, and nearly all the sarcode is removed from the sarcodous membranes by the same cause. ‘There are hirsute spicula very closely set and numerous on some parts of the depressions on the surface, protruding nearly the eighth of an inch, and im other parts of the sponge, where none of them appear above the surface, their remains are equally abundant when a section at right angles to the surface of the sponge is observed by the microscope, and it is therefore evident that at one period of its existence it was hirsute on all of its external parts. At the bottom of two deep, funnel-shaped depressions on the sponge, completely obscured by the great hirsute spicula, there appeared to be single oscula; these orifices were about the size of the large ones in Dr. Fleming’s specimen of C. Miilleri (Geodia Zetlandica), but I could not detect smaller ones, either single or in groups, on any part of its surface, in consequence of the uncertainty induced by the total destruction of the dermal membranes. Some parts of 4 50 A MONOGRAPH OF THE the surface exhibited stellate pittings very like those on the type specimen of C. Mulleri, but as these are only an acci- dental character, arising from contracting the tissues by drying, there is not much value in their stellate appearance. The form and proportion of the spicula and gemmules of all parts of the two sponges coincide; the only difference that I could note was that the hirsute spicula penetrating the crust of the Cape specimen were more numerous in a section examined than they appeared to be in a similar section from Dr. Fleming’s British type specimen; an amount of difference that would probably be found to exist in different parts of the same specimen. I cannot, there- fore, do otherwise than conclude, that they are the same species, notwithstanding the great differences that exist in their localities. The history of this sponge presents a singular sequence of errors. In the first place, Muller is distinctly wrong in the designation of his species, which undoubtedly is Alcy- onium of Ray and Linneus. Professor Jameson, perhaps misled by the stellate mantlings on the surface, believed the sponge from “ Fulah and Unst” to be the same as Muller’s specimen, and an Alcyonium. Dr. Fleming, at the time of the publication of his ‘ British Animals,’ appears to believe it to be not an Alcyonium, but still identical with Muller’s specimen, and accordingly gives it both a new generic and specific name. At last Johnston, seeing that it is not the type of a new genus, sinks both Dr. Fleming’s generic and specific names, and correctly assigning the specimen to Geodia, renames it Zetlandica. BRITISH SPONGIADA, 51 Genus, Pacoymatisma, Bowerbank. 1. Pacuymatisma Jounstonia, Bowerbank. Hauicnonpria Jonnstonia. Trans. Mic. Soc. London, vol. i, p. 63, pl. vi. _ _ Johnston. Hist. Brit. Sponges, p. 198. Sponge. Massive, sessile; surface smooth, undulating into ridges. Oscula simple, congregated on the ele- vations. Pores inconspicuous. Dermis crustular, filled with ovaria: dermal membrane pellucid, abun- dantly spiculous ; spicula fusiformi-cylindrical, tuber- culated, minute. Intermarginal cavities immersed in the dermal crust, separate, symmetrical, sub-cylin- drical, valvular at proximal end. Connecting spicula, attenuate or cylindro-patento-ternate, radii variable in form and proportions. Skeleton, spicula cylindrical, variable in form and proportions. Spicula of sarcode attenuato-stellate, radii incipiently spinous, rarely fully spinous, or obtuse. Ovaria oval, depressed. Colour.—Littoral specimens, light to dark slate gray. Deep sea specimens, pink or red. Capt. F. W. L. Thomas, R.N. Habitat.—Rocks between high and low water mark, Torquay, Guliot Caves, South Coast of Ireland, Bower- bank; Orkney Islands, 35 fathoms, Capt. F. W. L. Thomas, R.N.; Wick, Scotland, C. W. Peach. Hzamined.—In the live state. I described this sponge in a paper read before the Microscopical Society of London, November 24, 1841, from specimens which I found attached to the rocks between high and low water marks, and designated it Halichondria 52 A MONOGRAPH OF THE Johnstonia, but having subsequently consulted with my friend Dr. Johnston, of Berwick-on-Tweed, on the pro- priety of making it the type of a new genus, I afterwards named it Pachymatisma. The outer surface of the crustular dermis is quite smooth ; those parts of it in littoral specimens which are most exposed to the light, are of a dark gray colour, sometimes approaching black, while the marginal portions near the base are frequently of so light a gray as to be nearly white. The interior substance is of a dull yellow colour, firm ini texture, and very much resembling the crum of bread in appearance. ‘The thickness of the dermal crust varies from a quarter to half a line. It is composed of ovaria, closely embedded in membranous structure; the greater portion of them appear to have ejected their prolific contents and become solid, but near the surface single specimens or small groups are filled with this substance. Intermixed with the ovaria, there are also frequently to be observed round siliceous. molecules, of about the same diameter or rather less, than that of the adjoining spicula. The dermal membrane is thin, and abounds with short, stout, fusiformi-cylindrical spicula, which are more or less irregularly tuberculated; they are also dispersed abun- dantly on the membranes throughout the whole of the crustular dermis, and are found occasionally in the sarcode of the interstitial membranes, lining the excurrent canals. Their average dimensions are, length 3th in., diameter sooth inch. There is great variety in the form of the spicula, espe- cially in those connecting the crustular dermis with the body of the sponge. The normal form of the connecting spicula appears to be attenuato-expando-ternate, the radi being more or less acutely terminated, and having a long attenuating shaft terminating acutely. In other cases they are cylindro-expando-ternate, and frequently very stout in their proportions; and between these two forms every imaginable variety and malformation may be found, the radi being frequently bifurcated or contorted to a great BRITISH SPONGIADA. 53 extent. The ternate terminations are embedded in the inner surface of the crustular dermis, and the shaft passes into the body of the sponge beneath, at right angles to the surface, thus securely bracing the two parts of the sponge together, and forming areas for the valvular proximal terminations of the intermarginal cavities. The oscula frequently assume a linear arrangement on the elevated ridges of the surface. In the live state they are even with the surface of the sponge, and are furnished with a mem- branous veil, which apparently has the power of contrac- tion, so as to entirely close the osculum at the will of the animal. In the dried condition they are frequently sur- rounded by a slightly elevated ring, arising from the contraction of the membranous veil in drying. They are very numerous, but rarely exceed the eighth of an inch in diameter. In the living condition, the pores are not visible to the unassisted eye, but in the dried state they are very distinctly to be seen. They are very numerous, and occupy every part of the surface, excepting in the immediate vicinity of the oscula, near which they appear to be smaller than they are in the more distant portions of the space intervening between the groups of those organs. The normal form of the skeleton spicula is regularly cylindrical, with hemi- spherical termination of the same diameter as the shaft, but sometimes one or both of the terminations will be in- creased in diameter, so as to become sub-clavate, and at others, if it were not for the sub-hemispherical terminations of the lesser end, the form would be completely acuate ; or we find the terminations sub-hemispherical and the shaft fusiform, to a considerable extent. The arrangement of the interstitial membranes in the body of the sponge is strikingly similar to the mode of disposition of the membranous structure in the human lung when in a state of distension, and like it, they form the walls of continuous, irregular, and very much contorted cavities. When free of sarcode by maceration, they are thin, transparent, and destitute of spicula. In the living state the sarcode is in great profusion, and it is furnished 54 A MONOGRAPH OF THE abundantly with stellate spicula, and sparingly with the minute and irregularly fusiform ones which abound in the dermis. The stellate spicula are dispersed in considerable numbers in that substance ; they are remarkably large in comparison with those of Geodia ; an average-sized one measured 35,0 of an inch between the extremities of the radii, which vary in number from three to ten or twelve. The ovaria vary considerably in their proportions, those in a normal condition are from one and a half to two diameters in length ; an adult average-sized one measured, length 3th inch, diameter ;4rd inch. In their natural state, when viewed by direct light, they appear of the same colour as the surrounding tissues, but when viewed as transparent objects, the fertile ones present a dark central nucleus, varying considerably in size in different specimens, and in such ovaries the distal apices of the specula composing the shell are usually acute, or more or less rounded, while in the perfectly adult and fully developed ones, these ends of the spicula have a truncated angulated form, and the surface of the ovary has a smooth and even appearance, instead of being composed of sharp projecting points, as in the young and incompletely developed ones. After the discharge of their contents, the central cavity becomes filled up by a further development of the spicula inwards, and the process is also frequently continued in an outward direction, until the surface becomes tuberculated and distorted in a very remarkable manner. BRITISH SPONGIADA. 55 Genus—Kcionemia, Bowerbank. 1. Ecionemia compressa, Bowerbank. 20 = ponderosa, Bowerbank. EcionemMia compressa, Bowerbank. Sponge. Elevated on a short compressed pedicel, mass much compressed, surface even, smooth. Oscula simple, dispersed, small. Pores inconspicuous. Dermal membrane abundantly spiculous; tension spicula acerate or inflato-acerate, entirely incipiently spined, rather slender, numerous ; retentive spicula attenuato- stellate, large; and elongo-attenuato stellate, small, and very numerous. Connecting spicula attenuato- patento-ternate, radii long and rather slender, shaft rather short. Skeleton. Spicula acerate, rarely acu- ate, large, and long. Interstitial membranes abun- dantly spiculous; spicula the same as those of the dermal membrane. Colour.—Light gray. Habitat.—Shetland, Mr. C. W. Peach. Examined.—In the dried state. I am indebted to my friend Mr. Peach for this interesting specimen; the first British species I have seen of the genus. It was dredged by Mr. J. Gwyn Jeffrey, in 1864, and preserved for me by the donor, who accompanied the expedition. The sponge is in excellent preservation. It is three and half inches in height; two and three quarters in breadth, within about an inch of the distal extremity, and its greatest thickness is about four lines ; the height of the pedestal is three fourths of an inch, and 56 A MONOGRAPH OF THE its breadth nearly the same; and there are two lateral lobes of the sponge, which each extend downwards to about half the length of the pedestal, their inner margins being nearly in contact with its thin edges. The most distinctive characters in this species are those of the spicula of the dermal and interstitial membranes, and the tension spicula especially so; the incipient spina- tion is common to them all, but the central inflation of the shaft is not equally prevalent ; the greater number of them, perhaps, may be said to be deficient in that character, while in the other portion it is well developed, and always near the middle of the shaft. In many parts of the mem- branes, they are exceedingly numerous, and are always irregularly dispersed. The difference between the larger and the smaller stellate spicula in size is very considerable ; the former are usually simply stellate or slightly elongated, while the latter appear always to be decidedly elongo- stellate. A satisfactory definition of these spicula requires a linear power of five or six hundred. The connecting spicula are not very numerous, and are samewhat variable in size, their radii are often quite half the length of the shaft. I could not detect any recurvo- ternate spicula among them. 2, EcroneMIA PONDEROSA, Bowerbank. Sponge. Sessile, massive, lobate; surface smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane abundantly spiculous; tension spicula acerate, large, and long, dispersed ; retentive spicula elongo-stellate, very numerous, minute; and also attenuato-stellate, small, few in number. Connecting spicula furcated attenuato-expando-ternate, furcations of the radii recurvate ; shafts rather short. Skeleton, spicula very abundant, acerate, large, and long, irregularly disposed. Interstitial membranes ; tension spicula same as those of the dermal membranes; and doliolate cylindrical spicula, toth few in number; BRITISH SPONGIADZ. 57 retentive spicula same as those of the dermal mem- brane, few in number. Colour.—Alive ; dried, nut brown. Habitat.—Guernsey, Rev. A. M. Norman. Examined.—In the dried state. The sponge in its present condition is three inches in height by about two inches in its average diameter; at about two thirds of its height, it divides into two large rudely conical lobes, terminating obtusely, each being about an inch in height. My friend the Rev. A. M. Norman informed me that when fresh from the sea it was very much larger than it is in its dried condition ; that it was very ponderous and fleshy, and it was with great diffi- culty he succeeded in drying it, in the course of which operation it was exceedingly fetid. The dermis has a dense appearance in consequence of the abundance of the dark purple coloured sarcode with which it is lined, and the profusion of spicula embedded in it. ‘The tension spicula are very numerous, irregularly disposed, and cross each other in every direction. They are rather less in diameter than those of the skeleton, but in every other respect they closely resemble them. ‘The retentive spicula are remark- able from the paucity of spines at the middle of the shaft, so that in many instances they very closely simulate the rotulate form; they are exceedingly numerous and very minute, requiring a microscopic power of 700 or 800 linear to render them distinctly to theeye. The attenuato- stellate spicula, although small, are very much larger than the elongo-stellate ones. ‘The connecting spicula vary con- siderably in size, but when fully developed they are large and strong, but rather short in the shaft; the recurvations of the furcations of the apices of the radii of the expando- ternate terminations are usually at the bases of the forks, and they are abruptly and strongly produced. When per- fectly developed, these spicula are symmetrical in form, but they are subject to frequent malformations of the radii. The interstitial membranes are very abundant, and the 58 A MONOGRAPH OF THE spaces numerous and small ; the acerate retentive spicula are few in number, the abundance of the skeleton ones ren- dering their presence to a great extent unnecessary, and a few doliolate cylindrical spicula were disposed on the membranes. On some portion of the membranes the elongo-stellate spicula were thinly dispersed, but m many parts they were entirely absent. Genus—Potrmastia, Bowerbank. Sxction * * Skeleton spicula, acuate. 1. Polymastia ornata, Bowerbank. 2. — bulbosa, Bowerbank. 3. — robusta, Bowerbank. A — brevis, Bowerbank. 5. — spinula, Bowerbank. 6. — radiosa, Bowerbank. Sxcrion * * * Skeleton spicula, spinulate. 7. Polymastia mammillaris, Bowerbank. 1. Ponymastia onnatA, Bowerbank. Sponge. Sessile (?). Base unknown; fistula single, large, and long. Surface abundantly but minutely hispid. Oscula congregated at the distal extremity. Pores inconspicuous. Dermal membrane pellucid, rather stout, abundantly furnished with short and stout acuate spicula, based on the external surface of the membranes ; irregularly depressed, radiating in every direction. Skeleton: primary lines constructed of continuous large, compact, parallel, cylindrical fasci- culi of spicula, dispersed at regular intervals, and extending from the base to the apex of the fistula, in a slightly spiral direction. Secondary or interstitial BRITISH SPONGIADA. 59 skeleton formed of spicula of the same form and size as those of the primary fasciculi, irregularly disposed on the interstitial membranes. Spicula of skeleton acuate, large, and long. Colour.—Alive, cream white. Habitat. — About five miles off Whitby, Captain F. W. L. Thomas, R.N. Eaxamined.—In the dried state. I received two apectaphi of this sponge from my friend Captain F. W. L. Thomas, R.N., of the Hydrographical Survey. They were dredged about five miles from the Yorkshire coast near Whitby, in thirty-five fathoms. He destribed them as ‘‘ attenuated cylinders two or three inches long and a quarter of an inch in diameter, hollow, and flaccid, consisting only of a thin skin resembling white glove leather when recent.” Each of these specimens was about one and a half inches in length, and not quite three lines in diameter at the torn base, no part of the natural one being present ; and they were compressed into a strap shaped form. On opening one of them from the proximal end to the apex, it presented a regular and very beautiful arrangement of the tissues. The inner surface is furnished with a single layer of large, symmetrical, parallel bundles of spicula which proceed from the base to the apex, in an elongated spiral direction, making about one turn between the two extremities. The fasciculi are united by a beautiful wide network of interlacing bundles of spicula. Between the inner and outer surface of the sponge there are irregular interstitial cavities either two or three deep, or a single one, which extends from the outer to the inner surface; thus approximating very closely to the prin- ciple of the structure in the parietes of the genus Grantia. This beautiful and symmetrical arrangement of the tissues strikingly calls to mind the delicate and truly elegant sponge skeleton described by Professor Owen in the ‘Transactions of the Zoological Society,’ vol. iii, page 203, plate xii, and designated by him Zuplectella asper- 60 A MONOGRAPH OF THE gillum. This species and others nearly allied to it in the Museum of the Jardin des Plantes, at Paris, designated Alcyoncellum corbula, each, like the sponge under considera- tion, consists of a single, large fistula, without any promi- nent basal mass, but is simply cemented at, or near its basal extremity to any foreign body against which it may happen to press during its growth. The dernial membrane is translucent, but comparatively stout, and the external defensive spicula are irregularly dispersed on all parts of it, their bases being cemented on its outer surface, without any apparent reference to the secondary lines of the skeleton immediately beneath them, and they radiate from the surface in every possible direc- tion. From the structure of the network of the skeleton of the external surface of the sponge, it naturally results that the pores are congregated in the areas of the large reticulations, and within their spaces one or two open pores were occasionally observed, but in the specimens under consideration they were of rather rare occurrence. In the dried specimen, the inhalent areas are depressed to the extent of more than the length of a defensive spiculum, and it is probable that this depression existed to a certain extent in the living state. In a fragment of a specimen of this species, sent to me by Mr. Barlee, and consisting of the extreme apex of the sponge, there are no indications of compression or collapse, the terminal portion being hemispherical, exhibiting a series of areas strongly indica- tive of a congregation of oscula, and very unlike those of the parietes of the general mass of the sponge. The primary lines of the skeleton are situated at the imner surface of the sponge. They are rather distant from each other, and there are frequently more than one series of interstitial spaces intervening between them. The thickness between the outer and inner surfaces of the sponge is greater than that in P. mammillaris, and almost equal to that of P. robusta, although the general aspect of the sponge is more transparent, and apparently fragile than either of the fistular portions of those species. BRITISH SPONGIADA. 61 2. PoLyMAsTIA BULBOSA, Bowerbank. Sponge. Sessile, basal mass bulbous, apex of bulb termi- nating in a single fistula. Fistula gradually atten- uating from the base to the bluntly conical apex. Surface even, minutely hispid. Oscula terminal on the cloacal fistula. Pores inconspicuous. Dermis of basal mass thin. Dermal membrane pellucid ; dermis of the basal mass furnished abundantly with minute spinulate external defensive spicula, based on the external surface, irregularly dispersed. External defensive spicula of fistula same as those of basal mass ; congregated more especially above the lines of the skeleton tissues. Skeleton. Fasciculi rather widely apart, loosely compacted; spicula acuate, large and long. Colour.—Alive, and in spirit, cream white. Habitat—Shetland, Mr. C. W. Peach. Examined.—lIn spirit, as it came from the sea. This remarkable species was dredged at Shetland, in 1864. Its form is very much like that of a young onion just beginning to develop its bulb. ‘The basal mass is seven lines high to the base of the fistula, and its greatest diameter is six lines. The terminal fistula is nine lines in length, and one and a half lines in width, near its base; it is in a closely collapsed state, but in opposite directions, at different parts of its length, and it gradually decreases in diameter from its base to its apex, terminating in a bluntly conical form. The base of the bulb is firmly cemented to the remains of a large Balanus, in company with a young specimen of Dictyocylindus hispidus, the base of which spreads over a part of the shell, while that of P. bulbosa does not extend in the slightest degree beyond the point of its attachment. The solitary fistula and the general aspect of the struc- 62 A MONOGRAPH OF THE tures, at first led me to expect that it was a complete specimen of P. orzatus, but the characters of the spicula quickly dissipated that illusion. ‘he delicacy and thin condition of the structures of the fistula very closely assimilate them with those of P. ornatus, but while the latter has the external defensive spicula acuate, those of P. bulbosa are decidedly spinulate. 3. Potymastia RoBusta, Bowerbank. Sponge. Sessile, coating; surface even, smooth. Oscula terminal, congregated on numerous stout, long, mammeeform, cloacal fistule ; apices of fistulae ob- tusely conical. Pores inconspicuous. Dermis coria- ceous, armed abundantly with stout, ensiform spinulate spicula. Skeleton. Spicula super fusiformi-acuate, large and long. Interstitial membranes stout, com- pound, formed of layers of fibro-membranous tissue ; fibres parallel, layers disposed most frequently at right angles to primary skeleton fasciculi, occasionally diagonally to them. ‘Tension spicula acerate, very minute, rather few in number. Colour.—Alive and dried, fawn-yellow. Habitat——Coast of Northumberland, Professor Wm. King, of Galway; three miles off Dunstanborough, Northumberland, Rev. A. M. Norman. Examined.—In the dried state. The best specimen I have seen of this fine species was presented to me by my friend, Professor King, of Queen’s College, Galway. He informed me it was brought up by hook and line, in about 40 fathoms of water, about 40 miles from the Northumberland coast. The sponge coats a surface of about nine square inches, and has thirty-nine of the tubular mammeeform fistulae upon it, many of them exceeding an inch in length, but on BRITISH SPONGIADE. 63 not one of them in the dried state is there any indication of a terminal aperture. Professor King told me, “that the colour when alive was the same as in the dead specimen. That it was stiff and rigid when alive, and that no aper- tures were visible on the mamme.” In their dried con- dition they are strap-shaped by collapse; the largest of them are three lines in breadth at the base, and gradually tapering upward, terminate in obtuse cones. At the base, within each of the fistulz, there is a tolerably. stout, contractile membranous diaphragm; in one case examined, the membrane was entirely closed, in another there was a circular opening in the middle of it, equal to about one fifth or one sixth of the whole diameter, and in a third case the orifice in the diaphragm was equal to about half its entire diameter. It is evident, therefore, that the animal has a perfect control over the action of the fistule, and as each of these organs are furnished with pores on all parts of their parietes, so they also have the power of in- dependent inhalent and exhalent action, as well as the parent mass of the sponge. This power of regulating the vital action in one part of the sponge, independent of another part, is quite in accordance with a similar capability of suspension or alternation of action in the oscula of Hymemacedon caruncula, which I have described in m paper on the vitality of the Spongiade, published in the Reports of the British Association for 1856, page 435. ‘ The anatomy of the fistulae of this sponge, especially that of the fibro-membranous tissues, exhibits a high degree of organic structure, and indicates an amount and variety in the powers of action in these organs, unusual among the Spongiadze. It is unnecessary to notice the un- usually complex structures of these tissues at length, as they are sufficiently described at p. 100, in the first volume .of this work. A specimen of this species, about two and a half inches long, and not exceeding nine lines in breadth, detached from the body on which it grew, was dredged three miles off Dunstanborough, Northumberland, and was sent to me for examination by the Rev. A. M. Norman, in 64 A MONOGRAPH OF THE 1865. Itagyees in all its essential characters with the type specimen of the species. 4. PoLyMASTIA BREVIS, Bowerbank. Sponge. Sessile, or slightly pedicelled, massively clavate, short, somewhat compressed, consisting of a single large fistula. Surface even, minutely but profusely hisped. Oscula and pores inconspicuous. Dermal membrane aspiculous. -External defensive spicula acerate, or sub-fusiformi-acerate, short, very numerous ; projected at about right angles through the dermal membrane for about one fifth of their length. Skele- ton spicula. Super-fusiformi-acerate, large and long. Interstitial membranes ; tension spicula, acerate, or sub-fusiformi-acerate, short, numerous, frequently fas- ciculated. Colour —Ochreous yellow, dried. Orange, when alive. Habilat.—Shetland, 60 to 90 fathoms. Mr. Barlee, Rev. Mr. Norman, Mr. Peach. Ezxamined.—In the dried state. I received from my late friend, Mr. Barlee, eleven specimens of this sponge. One was based on the shell of a living vermetus, the remainder were on small pebbles. The basal attachment exceeded in its diameter very little that of the smallest part of the ascending column of the sponge, which in most cases gradually increased in size, from the proximal to the distal extremity, which in some, presented a hemi- spherical form, while in others it assumed a compressed and truncated appearance. The height of the sponges varied from six to eight lines; the base being about two lines in diameter, and the distal extremity about three or four lines. When divided longitudinally, the parietes of the sponge did. not exceed in the dried state, the fourth of a line in thickness at any part, and the internal cavity BRITISH SPONGIADZ. 65 extended the whole length of the sponge. The greater number of them were more or less in a compressed state, but in some there were strong indications that this was due rather to collapse than to natural form. The Rev. A. M. Norman sent me four specimens of this species, two preserved in spirit, and two in glycerine, as they came from the sea, none of them presented the com- pressed appearance of the dried specimens, but the greatest diameter of three out of the four was oval rather than circular. At the distal termination of one of these speci- mens there was a mammeformed projection of about half a line in height, that presented an appearance like that of a closed osculum; no other appearance of oscula were visible. The hispid character is rarely visible in the dried specimens with an inch lens, but when a portion of the sponge has been mounted in Canada balsam it becomes strikingly prominent, and the number of the spicula is so great as to completely obstruct the view of the dermal. membrane through which they pass. Their direction is at very nearly right angles to its surface, for about one fifth of their length ; their bases are intermixed with the trans- verse fasciculi of the skeleton beneath, and they penetrate the sponge to the extent of about half the thickness of its parietes. In a Specimen which I divided longitudinally, nearly the whole of the interior was empty; towards the base of the sponge there were a few irregularly disposed interstitial membranes, and on these the tension spicula were nearly all more or less fasciculated, but there was no regularity in the disposition of the fasciculi. In the sarcode of these membranes there were numerous small vesicles, filled with minute granules. The vesicles ranged in diameter from about once to twice the greatest diameter of a tension spiculum ; but they were all of them evidently more or less contracted, from having been dried. I did not observe these vesicles in any other part of the interstitial mem- branes. The number of the longitudinal fasciculi of the skeleton was from thirty-four to about forty, and their direction.was ~ 4 2 66 A MONOGRAPH OF THE nearly in straight lines from the base to the apex of the sponge. My friend, Mr. Barlee, states that in the living condition the sponge was of an orange colour, and semi-transparent, and that the reticulated structure was apparent through the surface. The interior was filled with a yellowish fluid, and the exterior slightly mucous. Since the above was written, I have received two other specimens of this species. One, remarkable for its com- paratively great height, the entire length being one and a half inch; the apex is obliquely truncated, and has two small mammeform projections, one at each angle of the apex. The other specimen presents a singular variety of form and size. It is an inch in height, and although now compressed, is as broad as it is high; it has apparently in its living state been as nearly as possible globular. These specimens were sent to me by my friend Mr. Peach. They were dredged at Shetland, in 1864, by Mr. J. Gwyn Jeffreys. 5. PoLyMastia spinuLa, Bowerbank. Sponge. Sessile, basal portion coating, thin; furnished with one or two, rarely three, long slender fistule. Surface hispid. Oscula congregated, terminal on the fistula. Pores inconspicuous. Skeleton. Fistule strap-shaped, distal terminations more or less hemi- spherical ; spicula of the primary fasciculi fusiformi- acuate, long and stout. External defensive spicula of both basal mass and fistulae spinulate, long and slender, more or less irregularly dispersed. Colour.—Dried, cream white. Habitat. — Moray Frith, Rev. Walter Gregor: Shet- land, Mr. Barlee, Rev. A. M. Norman, and Mr. Peach. LExamined.—In the dried state. The general aspect of this species is that of an incom- BRITISH SPONGIADA. 67 pletely developed specimen of P. mammillaris, or of one in which the production of the fistulae may have been supposed to have been arrested, and limited in number by adverse circumstances, but a closer study of the two species renders this idea admissible. The young of P. mammillaris always has a more or less thickened: base, and the incipient fistulae are short, thick, and conical. A young specimen from Mr. Barlee, dredged at Shetland, has the basal mass five lines in diameter and two lines thick, and it has three such in- cipient fistulee on its surface, the longest not two lines in height, and no hispidation of the surface can be detected with an inch lens. ‘The young fistulz are developed pre- cisely in the same manner on the circumference of a large specimen of the same species, two and a half inches in diameter, dredged at Orkney by Captain Thomas, and in several other specimens of intermediate stages of growth the same mode of development may be observed. We may, therefore, presume, that this is the normal mode of development of these organs in P. mammillaris. The same mode also obtains in P. robusta. The aspect presented by P. spinularia is very different. In a specimen sent to me by the Rev. Walter Gregor from the Moray Frith, seated in the hollow of a valve of a large water-worn Cardium, the base of the specimen is oval, four lines by three and not thicker than writing-paper. ‘There has been two fistulee produced, one has been broken off at the base, and the other is quite perfect ; itis compressed in different directions in its course from base to apex, but at its widest part it does not exceed half a line in width, and is nine lines in length, and the hispidation of its surface is comparatively strongly produced ; while an adult fistula of P. mammillaris measured one and a half lines wide and seven and a half lines long. In other specimens from Shetland, in the cabinet of the Rev. A. M. Norman, the length and breadth of the fistule are not so much out of proportion to those of P. mammillaris, but they all have but two or very rarely three fistule, and in other respects exhibit a close alliance with the specimens received from the Rev. Walter Gregor. The general habit of this species is, therefore, strikingly 68 A MONOGRAPH OF THE different from that of P. mammillaris. I deem it necessary to be thus particular in the description of differential characters as compared with P. mammuillaris, as their struc- tural characters appear to be so nearly allied, but a close scrutiny and comparison of the spicula of the two species exhibit sufficient differences to establish their separate identity on structural principles alone. ‘Thus, the skeleton spicula of P. mammillaris are larger, and in every specimen examined the bases of the fusiformi-acuate spicula exhibit more or less tendency to enormi-spinulation, while in those of P. spinala no such character is visible. The defensive spicula are as long as those of P. mammillaris but very much more slender, and the whole texture of the dermal surface more delicate and strongly hispid. 6. Potymastia RapIosa, Bowerbank. Sponge. Sessile, adherent through its whole length; body circular or oval, furnished with a single mammeform cloacal appendage; surface even, spiculous. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane pellucid, furnished abundantly with small short fusiformi-spinulate spicula matted together, and also with large radiating groups of external defensive sub-fusiformi spinulate, or sub-fusiformi acuate spi- cula, large, and long. Skeleton. Longitudinal fasci- culi few in number, large, dividing and anastomosing ; spaces intervening, usually smaller than the diameter of the fasciculi; spicula acuate, occasionally sub- spinulate, large, and long. Colour.—White. Habitat.—Shetland and Peterhead, N. B., Mr. C. W. Peach. a Examined.—In the dried state. _Uhave received two specimens of this species from my friend Mr. C. W. Peach. One found at Peterhead, and the other dredged at Shetland, in 1864. he form and BRITISH SPONGIADA. 69 habit of this little sponge is very singular. The shape is that of an oval battledore with a handle more or less long, adherent to the substance to which it is attached for its whole length, by one of its broad surfaces. The body of the sponge in both specimens is nearly of the same size and shape, but the mammeform cloacal appendage in one is only half a line in length, while in the other it is half an inch; in other respects, they resemble each other very closely. The shorter of the two specimens is from Shetland and is in a finer state of preservation than the one from Peterhead. I have, therefore, selected it for description. The length of the body is a line and a half, and its greatest breadth rather exceeding a line and a quarter; the cloacal appendage is half a line in length, and its medium breadth not quite a quarter of a line; its smallest diameter being at its apex, and its greatest breadth at the parts whence it springs from the body of the sponge. There are no indications on either specimen of the sponge ever having been in an erect position; on the contrary,both specimens are attached in precisely the same manner to the fragments of bivalve shells on which they were based, not by a few isolated points but bya close adherence of the whole surface. The entire thickness of the sponge does not exceed that of a sheet of writing-paper. Having care- fully removed the specimens from the shells and mounted them in Canada balsam, in the cloacal appendage there appeared three large longitudinal fasciculi of spicula, the intervening spaces being almost equal in breadth to the diameter of the fasciculi, and their bases can be traced for a considerable depth in the body of the sponge. In the second specimen in which the cloacal appendage is very much longer, there are as many as five of these fasciculi which divide and anastomose repeatedly in their course to the apex of the cloacal appendage. On the under side of the cloacal appendage there are numerous small spinulate spicula, crossing the large primary skeleton fasciculi at right angles to their axes in an irregu- larly matted manner ; and the margins of the cloacal ap- pendage are armed with numerous external defensive 70 A MONOGRAPH OF THE spicula projected at about right angles, to the surface ; they are sub-fusiformi, acuate, or sub-spinulate. On the broad side, that was attached to the shell near its distal portion, the longitudinal primary fasciculi were no longer visible, but in place of them there were numerous detached fasciculi of large fusiformi acuate and sub- spinulate spicula, immediately beneath the surface, irregu- larly crossing each other, but these fasciculi disappeared near the centre of the body of the sponge, at about the part where the primary longitudinal fasciculi were no longer to be seen; but, on the contrary direction, towards the basal portion of the sponge there is a manifest tendency to a disposition of the fasciculi in a radiant direction towards its outer margin. On the adherent surface of the sponge there appears to be but very few of the external defensive spicula developed, and those which were visible are in a recumbent position. The aspect of the exterior broad surface of the sponge is very different to that of the adherent one; here we have the whole surface bristling with the small external defensive spicula, and in addition to these there are large radiating clusters of long and stout sub-fusiformi-acuate, or sub-spinulate spicula. They spring from a closely compacted base and radiate thence at every possible angle, giving to the surface a very remarkable and beautiful appearance when examined in Canada balsam with a power of about 100 linear. These radiating groups of spicula, and the profusion of external defensive ones, that exist in the smaller of the two specimens are nearly all absent in the larger specimen, which appears as if 1t had been denuded by abrasion. In the latter specimen, there are on the upper surface of the body of the sponge several well-produced oscula and a few smaller ones appear towards the distal portion of the cloacal appendage ; but no such organs are to be found in the smaller of the two specimens. BRITISH SPONGIADA. 71 7. PoLyMastTIA MAMMILLARIS, Bowerbank. SPONGIA PENICILLUS, Montagu. HaicHonDRIA MAMMILLARIS, Johnston, Sponge. Massive, sessile. Surface even, hispid. Oscula terminal, congregated on slender mammeform cloacal fistulee ; rarely simple. Pores inconspicuous. Dermis of the basal mass sub-crustular. Dermal membrane pellucid, aspiculous. Dermis of the cloacal fistule furnished abundantly with radiating fasciculi of secondary external defensive spicula; spicula based on the external surface. Skeleton. Fistule numerous, strap-shaped, frequently truncated, or somewhat ex- panded at their distal terminations. Spicula of the primary fasciculi fusiformi-enormi-spinulate, rarely fusiformi-acuate, long and stout. External defensive spicula of basal mass, same as those of the skeleton. External defensive spicula of fistule fusiformi-spinu- late, short and small, very numerous ; congregated in radiating fasciculi, and based on the dermal mem- brane. ‘Tension spicula fusiformi-spinulate, variable in size. Colour.—Light ochreous yellow. Habitat—Lame Lough, Mr. Hyndman; Guernsey, Rev. A. M. Norman; Shetland, Mr. Barlee; Orkney Islands, Capt. F. W. L. Thomas, R.N. Examined.—In the fresh and dried states. I am indebted to my friend, Mr. George Hyndman, of Belfast, for two fine specimens of this species, each about two and a half inches in diameter, and about half an inch in thickness. Both have the appearance of having coated water-worn stones. The cloacal fistule are very abundant on both specimens ; their average length is about six or seven lines, and their width a line and a half; they are compressed for the whole of their length, and the distal 72 A MONOGRAPH OF THE extremities are often expanded laterally to the extent of half as much more as the average width of the tube. I am also indebted io the Rev. A. M. Norman, for the examina- tion of a specimen of this sponge, which was dredged up on the coast of Guernsey, in the autumn of 1859. It is attached to a piece of an old oyster shell. It is irregularly conical in form, an inch and three-quarters in diameter at the base, and its greatest height seven lines. The hispid character of the surface is visible to the unassisted eye, There was one or two simple oscula, probably due to the destruction of as many fistule while alive, the largest not exceeding half a line in diameter, the remainder of them, about sixteen in number, were all more or less mammeform, but apparently not in a fully developed condition, the tallest of them not exceeding two lines in height, and the greater portion were in a closely collapsed state. The fasciculi of skeleton spicula running longitudinally from base to apex of these cloacal appendages, do not appear to deviate from a straight line. The primary external defensive spicula of the basal mass of the sponge are continuations of the fasci- culi of the skeleton, but the secondary series of external defensive spicula of the same mass have their bases beneath the dermal membrane, through which, in the dried state, they are projected for about one third of their length, and as they are exceedingly numerous, their presence gives a sub-crustular character to that portion of the dermal struc- ture. This sub-crustular texture does not exist in the cloacal fistulee. In these portions of the sponge there are no primary defensive spicula, but their surfaces are abun- dantly furnished with secondary defensive spicula, which are based on the external surface of the dermal membrane. ‘They are mostly collected into radiating fasciculi, imme- diately above the transverse fasciculi of the skeleton, but a few of them spring singly from the surface of the dermal membrane in the spaces between the skeleton fascicull. On many of the cloacal fistulas they were so numerous as to render it very difficult to determine correctly their true positions. The tension spicula of the interstitial membranes are of BRITISH SPONGIADA. 73 the same form as those of the secondary series of external defensive ones, but they are usually much larger and longer. I have compared the specimens sent me by Mr. Hyndman, from Larne Lough, with the type of Montagu’s Spongia penicillus, in the possession of Dr. Grant, and there is no difference between the two, either in external appearance or in structural characters. Montagu says :—“ In drying, the tubes become compressed and a little arcuated, and all incline the same way ;” and this is precisely their condition in the Larne Lough specimens, not only when dried, but when preserved in spirit fresh from the sea. No reasonable doubt therefore, remains, that the specimens dredged by Messrs. Thompson and Hyndman i in Strangford Lough, in 1835, and sent to Dr. Johnston, and those dredged by Mr. Hyndman in Larne Lough, which were sent to me, are identical with Montagu’s Spongia penicillus, and are therefore entitled to be considered as correct types of Johnston’s Halichondria mammillaris. It is necessary to be thus particular in our recognition of the species, as a doubt might otherwise hereafter exist as to whether the sponge sent to me by Professor King, and designated by me Polymastia robusta, might not have been the original Spongia mammillaris of Johnston. Montagu in describing Spongia peniciilus, writes that :— «The interior substance of this species is precisely that of (Tethea) lyncurium, but instead of being orbicular, it spreads horizontally upon marine bodies, and shoots upwards from its surface cylindrical tubes, of nearly an inch in length, which have an opening at the apex.” Dr. Johnston, pro- bably on the authority of Montagu, repeats this assertion ; but in the dried type specimen from Montagu’s collection, there are no remains of such an open condition of the tubes as that described by him in the Wernerian Memoirs, and in no specimen of this or any other allied species of Polymastia, have I even been able to discover any such opening, or any distinct indication of such an opening, and I can only account for Montagu’s assertion that such open- ings existed in any specimen in his possession, by the supposition, that the apices of the cloacal fistulee had some 74 A MONOGRAPH OF THE of them been broken off. This supposition is supported by the fact, that in the large Species of the closely allied species, Huplectella aspergillum, Owen (Aleyoncellum, Quoy et Gaimard), no such large opening exists; the distal ter- mination of the sponge being permanently closed by a strong network of spicula, in the areas of which the oscula are placed, the whole of them being congregated at the apex of the sponge. Nor can I agree with Montagu, that the structure of the skeleton is similar to that of Zethea lyncurium, which consists of numerous slightly curved fasciculi of spicula, radiating from the base to all parts of the external surface of the sponge, while in P. mammillaris the skeleton of the basal mass consists of a plexus of contorted anasto-- mosing fasciculi, with short bundles of skeleton spicula disposed on the inner surface of the dermal crust of the sponge, at about right angles to its plane, and which ter- minate acutely. In the adult sponges these fasciculi are continued through the dermal surface, and from the series of primary defensive spicula, and are exceedingly numerous in the Larne Lough specimens, while in the immature sponges they are very sparingly produced. I received from Mr. Barlee, in June, 1856, two separate fistulee of this species, neither of them had the basal termi- nation. They were rather longer and larger than the fistulee of the specimens from Larne Lough, and their distal terminations were more attenuate and rounded, but struc- turally they exhibited no difference whatever from the Irish and Guernsey specimens of the species, and I subse- quently received from the same gentleman in June, 1858, four small specimens of this species, which he dredged up at Shetland ; they were all more or less depressedly conical, and they varied in diameter at the base, from four lines to an inch. ‘The smallest, four lines in diameter, had not a single mammilla on its surface, but the other three were amply supplied with them. ‘They were all short, and had more of the characters of mammee than of fistula, and the same peculiarities were observable in a specimen of about an inch in length by half an inch in width, that my friend, BRITISH SPONGIADA. 75 Captain ‘Thomas, of the Hydrographical Survey, sent me from Orkney. These peculiarities also agree with those which I have described as characterising the Rev. A. M. Norman’s specimen from Guernsey. ‘None of these specimens had elongated fistular cloacal appendages, with a truncated distal termination, which are so abundant on the Larne Lough specimens, while in the latter a few of the short mammeeform organs are found at the extreme margin of the sponge. In the structural characters of the young specimens we also find slight differences arising from immaturity. Thus the spicula in the young sponge are neither so long nor so stout as those of the mature ones, and the spinulate characters are not quite so fully developed as in those of the Larne Lough specimens, but in every other respect there is no essential structural difference. I have thought it important to mention these differences existing between the immature and the mature specimens, that hasty observers may not be led to believe them to be distinct species. The incre- ment of the sponge is effected by a progressive extension of the dermal crust of the basal mass. On removing a small portion of this part, and mounting it in Canada balsam, it presented very much the same appearance as that of a small portion of an adult fistula. A series of parallel bundles of spicula in the direction of right angles to the margin of the sponge, connected by secondary skeleton fasciculi, in the areas of the reticulations of which the pores were seated. 76 A MONOGRAPH OF THE Genus—Hatyruysema, Bowerbank. 1. Halyphysema Tumanowiczit, Bowerbank. — ramulosa, Bowerbank. 1. Hatypuysema Tumanowiczi1,* Bowerbank. Sponge. Pyriform, pedicelled, base expanded, thick, turgid at the margin; pedicel gradually enlarging upwards, fistular, parietes very thin, surface smooth and even ; distal extremity abundantly hispid. Oscula and pores inconspicuous. Dermal membrane thin and translucent. Skeleton. Membranous, with an incorporation of fragments of spicula of various sizes and forms, and of minute grains of sand. Colour.—Alive ; bluish white; milk white when dried. Habitat.—Diamond Ground, off Hastings, Mr. Tumano- wicz ; Berwick Bay, Dr. Johnston ; Cullercoats (?), Mr. Alder. . This species is remarkable as being the smallest known British sponge. It rarely exceeds a line in height. It is found based on the stems of small fuci and zoophytes, and. frequently in considerable numbers. It varies but little from the normal form, but occasionally the pedicel is com- paratively considerably elongated, and it is then often more or less contorted. The distal end is usually pyriform, but sometimes it is found nearly globular, and in one case it was projected at nearly right angles to the axis of the pedicel. When seated on a flat surface, the base of the sponge has much the same form as half of an orange * Pronounced Tumanovitchii. BRITISH SPONGIADA. 77 divided at right angles to the axis of the fruit, and placed with the convex portion uppermost; and like the fruit it has a depression in the middle of the upper surface, from the centre of which springs the pedicel, which has its greatest contraction at its junction with the base of the sponge. from which part it increases gradually upwards, and finally enlarges into the pyriform distal termination. The attachment of the proximal end of the pedicel with the expanded base of the sponge is very singular. In some cases, I observed the end of the pedicel did not appear to be an open tube springing from the circular line of junction in the base of the sponge; but, on the con- trary, it was contracted and apparently closed in a hemis- pherical form, and it looked asif it had been fixed into the base by having been, as it were, plugged into a previously existing hole on its summit, and the external and internal junction lines were sharp and angular. From this point upwards the pedicel gradually enlarges until it expands into the pyriform head. The whole sponge, the hassock- shaped base, as well as the pedicel and head, are hollow, and the thickness of the parietes is very inconsiderable. The arrangement of the spicula of the skeleton in the base is decidedly irregularly reticular, and it is singular that the network in almost every case appears to be com- posed of fragments instead of perfect spicula. In the pedicel, the spicula are dispersed, with very few exceptions, in lines parallel to the long axis of the sponge, and the short acerate spicula are more especially found in this part. Intermixed with the spicula of the pedicel there are frequently grains of sand and other extraneous matter embedded, apparently to increase its strength, and this intermixture more particularly occurs in the elongated ones. Occasionally, very stout and large spicula are found in the pedicel, and in one case an exceedingly large and stout triradiate one projected one of its rays at right angles from its axis, the other two running nearly parallel to the axial line of the pedicel. The head of the sponge is abun- dantly furnished with defensive spicula which radiate in all directions between lines in accordance with, or at right angles 78 A MONOGRAPH OF THE to the axis of the sponge, but I have never observed them to assume a backward direction. These spicula are of great size in comparison with the dimensions of the sponge, frequently projecting beyond the surface of the head to the extent of one and a half, and sometimes twice the amount of its greatest diameter; and what is rather re- markable, it often occurs that the hemispherical heads of the acuate, and the globular heads of the spiculate spicula are the distal instead of the proximal portions of the spicula; and in one instance, among the projecting spicula, was an enormous triradiate one, having one ray based on the top of the head of the sponge, the other two being projected from its apex. I have been unable even with a high microscopical power to detect either oscula or pores. Nor have I succeeded in separating any portion of the dermal membrane from the sponge, but seen zz situ it is evidently thin and translucent. I first obtained this interesting little species from Mr. Tumanowicz, of Hastings, who informed me that he received it from the fishermen trawling off that coast, at the Diamond Ground, in about twenty-five fathoms; he has also found it on zoophytes, cast up on the beach after severe storms; we may, therefore, consider it as a deep sea species, from seven or eight to twenty-five fathoms. Halecium Beanii appears to be its favorite location, and on this zoophyte it 1s usually found in great abundance. He has also found it but in much less quantity on Plumaria falcata, and cristata, and Sertularia, argentia, operculata, and abietina; a few specimens only have been found on Alga, Phyllophora rubens, and Plocamium coccineum. When fresh from the sea, he states it is of a translucent bluish white colour. I have attached his name to it as an acknowledgment of the good service he has rendered to science by his indefatigable pursuit of marine natural history, and of the kind and liberal assistance that I have at all times received from him. I have also subsequently received specimens of this species from Mr. Alder, of New- castle-on-'T'yne, and from my kind friend Dr. Johnston, of Berwick-on-'l'weed. BRITISH SPONGIADA. 79 2. HALYPHYSEMA RAMULOSA, Bowerbank. Sponge. Pedicelled, ramose ; branching dichotomously ; branches cylindrical, smooth, and even; distal termi- nation sub-globose, hispid. Oscula and pores incon- spicuous. Dermal membrane thin and translucent. Skeleton. Membranous, with an incorporation of fragments of spicula of various sizes and shapes, and of minute grains of sand. Colour.—Cream white when dried. Habitat.—Guernsey, Rev. A. M. Norman. Examined.—In the dried state. This little sponge was found by the Rev. A. M. Norman on a fragment of the skeleton of an old Gorgonia verrucosa, brought up by the dredge off Guernsey. The specimen does not éxceed two lines in height and about the same in breadth, and in this space there are eight branches deve- loped, they are all of the same diameter, and each termi- nates in a bulbous expansion, of a rather depressed form, from which numerous large spicula are projected forward at various angles. The parietes of the tubular body are very thin, and the outer and inner surfaces rarely exhibit any projecting parts of the heterogeneous materials com- posing it. In its construction it seems to have appropriated fine particles of sand and fragments of spicula indifferently. The fragments of spicula are very various, some are of large diameter, others very slender, but all seem to have under- gone an approximation towards an arrangement, being dis- posed in the same plane, and they are frequently parallel to each other. There is also a method apparent in the selection and incorporation of the extraneous material of the skeleton that is very remarkable ; the grains of sand all appear to be within a certain range in size, and beyond this all large ones seem to be rejected. In lke manner, the fragments of spicula embedded in the parietes are all 80 A MONOGRAPH OF THE of such a length as to be easily disposed of symmetrically, but in the armature of the distal bulb, the spicula appro- priated are large and generally in perfect condition. The spinulate ones frequently have their bulbous bases outward, and the same reversals of position occurs with the acuate forms. These peculiarities of position are strong evidence of their extraneous character. Their attachment to the heads of the sponge would otherwise lead us to suppose they were all really secreted by the animal, as their attached . extremities are enveloped by the membranous and sarcodous tissues of the sponge, and these are continued around them for some distance upwards, while thin webs of dermal membrane connect the attached portion of the spicula with each other just as if they were the proper secreting organs of the spicula they envelop. These peculiarities of habit and structure are similar to those prevailing in Dysidea with the difference that one is productive of fibrous tissue, while, on the other, the development is tubular. I could not detect any peculiarities in the basal portion of the sponge, such as exist in that of H. Zumanowicez, and the sponge is larger in all its parts than in that species ; the branches were from two to three times the diameter, and the bulbous heads were in the proportion of four and a half to two, or two and a half the size of those of Z, Tumanowiezit. The acquisition of this species has thrown more light on the peculiarities of structure and habit of the genus Haly- physema, and it is a question whether in a future re-arrange- ment of the sub-orders these sponges should not be removed from Sub-order I to Sub-order IL; the essential base of the skeleton being membranous. BRITISH SPONGIADA. 81 Genus—CtocaLreta, Bowerbank. 1. ClocaLypTa PENICILLUS, Bowerbank. Sponge. Massive, sessile, composed of numerous closely- packed, attenuating, penicillate branches rising perpen- dicularly from a common base; branches gradually attenuating, occasionally bifurcating near the apex; apices rather obtuse, entirely closed. Oscula simple, small, dispersed ; largest and most numerous near the base of the sponge, minute on the branches. Pores inconspicuous, dispersed, numerous. Dermal mem- brane smooth, abundantly spiculous, same as those of the skeleton, fasciculated, forming a strong irregular reticulation. Skeleton. Spicula fusiformi - acuate, stout, variable in size. Colour. —Alive, light gray. Habitat.—Diamond Trawling Ground, off Hastings. Ewamined.—Alive. This sponge is four inches in height, and three and a half inches im average diameter. It is nearly cylindrical and has much the form it would have attained had it been grown in a short half-pint drinking mug. The penicillate branches originate on the basal mem- brane of the sponge, and are cemented to each other late- rally for about two thirds of their height, and some of the marginal ones for nearly or quite the whole of their length, the greater portion of them attenuate gradually to their apices, but a few of them bifurcate irregularly at about half an inch from their summits. In the living condition their surface is slightly rugged or tuberculated, the impinging of the distal terminations of the pedicels within causing this appearance, and this character is much exaggerated in 6 82 A MONOGRAPH OF THE the dried sponge. In this state the dermal membrane pre- sents very much the same beautifully reticulated appear- ance that is so striking a character in dried specimens of Halichondria panicea, and the size, number, and mode of disposition of the pores closely resemble those of HZ. panicea. I could find but one form of spiculum in this sponge, the fusiformi-acuate one; they varied considerably in size and diameter. This species is the only specimen of the genus I have yet seen. In treating of the generic character of this sponge, I have described the peculiarities of its struc- ture so fully as to render any further description of them unnecessary. Since writing the above description I have obtained a second specimen from the same locality. The only notable difference is in size. The basal portion is irregular in form, two inches in length, and one and a half in breadth, and the average thickness is about half an inch. ‘There are eighteen penicillate branches, the longest of them does not exceed an inch in height from the basal membrane of the sponge to its distal point, and its dia-— meter over the base slightly exceeded two lines. It decreases gradually from the base to the apex, and terminates acutely. The whole of these small branches are of the same form. Towards the centre of the basal mass there are the remains of several very much larger branches which have been torn off slightly above the surface of the base of the sponge, the wounded terminations have been covered with dermal membrane, but the ends of the central columns within are distinctly to be seen through the new membrane. There is a remarkable peculiarity in this specimen. All the small penicillate branches have the side nearest the outer margin of the sponge nearly smooth, while the oppo- site one abounds in mammeform tubercles from base to apex ; this peculiarity of the outer surface is probably due to the abrasion and pressure from other bodies which were growing around it. BRITISH SPONGIADA. 83: Genus—Tutura, Lamarck. Section * Skeleton spicula, acerate. 1. Tethea cranium, Lamarck. 2. — Collingsii, Bowerbank. 3. — Schmidtii, Bowerbank. Suction * * Skeleton spicula, acuate. 4. Tethea lyncurium, Johnston. Srction * * * Skeleton spicula, spinulate. 5. Lethea spinularia, Bowerbank. 1. Teruea cranium, Lamarck. TETHEA CRANIUM, Johnston, Sponge. Ovoid or subspherical, sessile. Surface even, strongly hispid. Dermal coat thick, abundantly furnished with short, stout, fusiformi-acerate spicula surrounding the large defensive fasciculi at various angles to their axes, also profusely furnished with minute sigmoid bihamate spicula, dispersed irregularly. Dermal membrane thin, pellucid. Oscula and pores incon- spicuous. Spicula of the skeleton fusiformi-acerate, large and long. Defensive spicula external, collected in fasciculi; fusiformi-acerate, large, and long; fusi- formi-porrecto-ternate, and a few fusiformi-recurvo- ternate very long and slender. Sarcode abundantly furnished with minute sigmoid-bihamate spicula. Gemmules internal, lenticula, surface smooth, very tough and strong; of two distinct sorts. The first furnished abundantly with slender fusiformi-acerate spicula radiating in fasciculi from the centre to near the surface of thegemmule. The second furnished abun- dantly with slender fusiformi-acerate; slender uni- 84 A MONOGRAPH OF THE hamate attenuated ; and with short, slender porrecto- ternate spicula, mixed in fasciculi which cross each other irregularly. Colour.—Alive, pallid green. Habitat—Island of Fulah, Jameson; Haaf Banks, Shetland, Mr. Barlee, Mr. J. G. Jeffreys, Mr. Humphreys. Examined.—Iin the living condition. I obtained nearly three hundred specimens of this sponge from the Shetland deep sea fishermen through their agent Mr. Humphreys. The largest I have seen was somewhat depressed, and was nearly three inches in its greatest diameter. The smallest did not exceed a large pea in size. They vary in proportions from being nearly globular to about, one and a half, their greatest diameter in height. The general description of this sponge by Dr. Johnston in his ‘ History of British Sponges,’ p. 83, is very correct as far as it goes. The central nucleus spoken of by that author is simply the concentration of the proximal ends of the fasciculi near the centre of the sponge, and in elongated specimens it is continued upwards as the sponge increases in height. The fasciculi radiate from the short central axis in curves or straight lines, and apparently as often in one way as the other, and there is no difference in the form or size of the spicula from their origin to their termi- nation, when they become intermixed with the defensive spicula of the surface. Their average size is jth inch long, th inch largest diameter. The surface is even, but is pierced in all parts by stout bundles of defensive spicula which originate beneath the inner surface of the dermal crust, among the distal apices of the fasciculi of the skeleton, and project beyond the external surface frequently as much as jth of an inch. In the young specimens, these fasciculi consist principally of slender fusiformi-porrecto- ternate spicula, and their furcate apices form very beautiful objects for the microscope, but they are generally broken off in the older specimens. Interspersed with these there are usually a few long, stout, fusiformi-acerate ones, and a few slender but very long fusiformi-recurvo-ter- BRITISH SPONGIADA. 85 nate spicula. The manner in which these fasciculi are strengthened and supported in their places is very remark- able, they are, as it were, each buttressed in its position by numerous comparatively short fusiformi-acerate spicula, which are based on the inner surface of the thick dermal coat of the sponge, and leaning from all parts around the fasciculus, their apices are concentrated around it, forming a most efficient conical buttress to it in its progress through the somewhat soft and yielding mass of the dermal crust of the sponge. These spicula do not reach the external surface of the sponge, but terminate in a cone about one third or one fourth the thickness of the dermal crust within its distal surface. ‘Their dimensions are, length jth inch, greatest diameter ,!,th inch. Disposed in the surrounding sarcode there are an abun- dance of very minute contort bihamate spicula. These spicula are remarkably minute, an average-sized one which - I measured was zj,rd inch long, and scth inch diameter, about the middle of the shaft. They are of a contort sigmoid form, and until a section of the sponge is immersed in Canada balsam they are not readily to be seen zz sztw. Dr. Johnston, in page 82 of his ‘ History of the British Sponges,” says, “In the native species of Tethea there are neither pores nor oscula, and Mr. Edward Forbes informs me that in the living 7. cranium, he did not observe any currents of water passing into or from the body. Adouin and Milne-Edwards, however, have seen their currents. When a Tethea, they tell us, is placed in a basin filled with sea water, and left for a considerable time perfectly still, we then see distinctly all the oscula agape, and we perceive also the currents which pass through them. But if the animal is irritated, or withdrawn for an instant from the water, the currents slacken or are altogether arrested, and the oscula contracting slowly and insensibly, become at last almost close.” ‘Hist. Nat. du Litt. de la France,’ i, p.-78- Although I carefully examined a considerable number of specimens, I could not detect either oscula or pores. | The interior of the sponge is very close and solid, and the inter- stitial canals few in number. I cut a large specimen into 86 A MONOGRAPH OF THE thin slices at right angles to the surface, but could not detect in the dermal crust anything in the shape of oscula or intermarginal cavities. At the same time, I believe MM. Adouin and Milne-Edwards’s observations to be per- fectly correct, and especially so as we are now aware that in Hymeniacedon caruncula and Spongilla fluviatilis, the oscula are opened and closed in precisely the manner de- scribed by those authors, and in the latter genus the pores have also the same power of opening at the will of the animal; and that when in a closed condition, no indication of their presence is visible in the dermal membrane. A portion of the spicula of the skeleton become external defensive ones, beg intermixed with the defensive fascicult. The true defensive spicula, the fusiformi-porrecto-ternate ones are exceedingly long and slender, and are frequently flexible near the attennated base. An average sized specimen which JI measured was ith inch in length and ;4;th inch in its greatest diameter. The fusiformi- recurvo-ternate spicula which occasionally accompany the porrecto-ternate spicula average ;th inch in length, and their greatest diameter was ,,;th inch. The sarcode is dense and semi-opaque, and abounds with the same minute sigmoid bihamate spicula that are found in the dermal crust. There are two distinct sorts of gemmules in this sponge which are always grouped together. The first is rather the smaller of the two, and has a nucleus of slender curved fusiformi-acerate spicula; only the bases of the spicula cross each other at the centre of the gemmule, and the apices radiate in all directions towards the external surface, but do not in the fully-developed state of the gemmule project beyond it. The second sort of gemmule is furnished with three distinct forms of spiculum. The first are like those of the gemmule deseribed above, slender fusiformi-acerate, the second are attenuato-porrecto-ternate, the radii being given off from the apex, at about an angle of 45°; and the third form is attenuato-bihamate or unihamate, and the hooked apices of this form are projected further than either of the other two forms, but do not pass beyond the BRITISH SPONGIADA. 87 inner surface of the tough dermal envelope of the gemmule when in the adult state. I have examined a great number of these gemmules, and could never find in the form first described any indica- tion of either ternate or hamate spicula in any of them, and I am, therefore, satisfied that they are separate de- scriptions of gemmule, and that the first form is not a transition state from the young and undeveloped to the fully developed form ; and in like manner I have closely observed the second form, and have always found it uniform in character, and furnished with the whole three forms of spicula that characterise it. It is highly probable that this marked difference in structure is sexual, and from the more highly developed condition of the second or largest form that it is the female or prolific gemmule, but on this point we must at present be satisfied with conjecture only, as, although I have searched ‘diligently for spermatozoa, in both forms of gemmule, and in the surrounding sarcode, I have not been able to detect any thing resembling them. This occurrence of two distinct forms of gemmule in the same sponge is the first case of this singular fact that has come under my observation, and is the only indication of pro- bable sexuality in the Spongiade that I have ever met with. The short porrecto-ternate spicula of the gemmule are ath inch in length, and the unihamate ones ,,th inch in length. When a gemmule is viewed in water by transmitted light, and a power of 150 linear, we find that it is thickly but indistinctly maculated. 2, Teraea Cottinesi, Bowerbank. Sponge. Massive, sessile, depressed. Surface uneven and rugged. Oscula and pores inconspicuous. Dermis thick and dense ; dermal membrane pellucid, furnished abundantly with minute acerate tension spicula; and, also, with attenuato-stellate retentive spicula, large and small, and also cylindro-stellate spicula, minute. 88 A MONOGRAPH OF THE Connecting spicula attenuato-recurvo-patento-ternate ; radii short, stout, and abruptly recurved near their apices. Skeleton. Spicula fusiformi-acerate, stout. External defensive spicula fusiformi-acerate, short, and slender. Interstitial membranes. Tension spicula, acerate, slender ; retentive spicula, same as those of the dermal membrane, very abundant. Colour.—Alive. External, somewhat green; internally, light gray. Habitat.—Guliot Caves, Sark, J.S. Bowerbank ; Round- stone Head, near Paignton, Torbay, Mr. Gosse; Tremain Bay, Guernsey, fifteen fathoms, Rev. A. M. Norman. Exanined.—In the living state. I received a portion of this sponge from the late Mrs. Buckland, who, I believe, obtained it from Mrs. Collings, the lady of the Seigneur of Sark; and in 1860, I found the specimens I have described in the second of the Guliot Caves at Sark. I believe it to be of rare occurrence, and it was very difficult to distinguish it from the well covered surface of the rock to which it was strongly and broadly attached. ‘The specimen I have is not above half its own diameter in height. It has a broad, flat, uneven surface, nearly two inches in diameter, with a deep cavity near its centre, and has much more of the aspect of a coating species of Geodia or Pachymatisma than that of the normal bulbous form of a Tethea. The dermal coat is very dense, and in some parts it rather exceeded two lines in thickness. ‘lhe connecting spicula are fasciculated, their bases converging to and uniting with the radial fasciculi of the skeleton where their distal terminations are radiated in all directions until they reach nearly the inner surface of the dermal membrane through which they rarely pass. A second and a more irre- gular series of ternate spicula exist immediately beneath the inner surface. and their recurved radii are frequently ’ projected into the intermarginal cavities of the sponge, apparently effecting the office of defensive spicula in those BRITISH SPONGIADA. 89 spaces. The whole of the connecting spicula are large and stout, with the radii very short, and abruptly bent backwards. In the canals which pass through the centre of the radii from base to apex there is frequently a small globular dilatation at about half their length, and occa- sionally the same canals assumed a somewhat moniliform character, but whether these minute peculiarities are acci- dental or specific it is difficult to say from a single specimen. The external defensive spicula are few in number, and not very regularly disposed. The stellate spicula‘abound most near the surface of the sponge, and especially the larger ones, and the membranes lining the large confluent inter- marginal cavities are thickly studded with them ; the three varieties of their form are intermixed near the surface, but in the deeper portions of the interstitial membranes the cylindro-stellate form prevails to a greater extent than the attenuato-stellate ones. Since the above description was written I have received a small fragment of this species from my friend, Mr. Gosse, who “ picked it from the under-side of a boulder at Round- stone Head, near Paignton, Torbay.” It agrees in every structural character with the specimen I found at Sark. T. Collingsii and T. Schmidtii closely resemble each other, both in external appearance and in structure, but they may, when mounted in Canada balsam, be readily separated by the difference in form of the external defensive spicula. In the former they are acerate ; in the latter they are spinulate. I have dedicated this species to Mrs. Collings, the lady of the Seigneur of Sark, to whose active researches in marine natural history we are indebted for our knowledge of the species. 3. Ternea Scumiptit, Bowerbank. Sponge. Massive, sessile, depressed. Surface minutely hispid. Oscula and pores inconspicuous. Dermis thick and dense. Dermal membrane abundantly spi- culous ; tension and external defensive spicula of the 90 A MONOGRAPH OF THE same form spinulate, ‘small, and slender; retentive spicula attenuato-stellate, rather large, with few radii ;* and minute cylindro-stellate, radii numerous. Skeleton. Fasciculi multispiculate ; spicula fusiformi-acerate, stout. Connecting spicula attenuato-recurvo-patento- ternate; radii short, stout, and abruptly recurved near their apices. External defensive spicula spinulate, small, and slender, variable in size, and often flexuous. Interstitial membranes abundantly supplied with the same forms of stellate spicula as those of the dermal membrane. Colour.—Dried, dull ochreous yellow. Habitat— Guernsey, Mrs. Buckland; Herm, Rev. A. M. Norman. Exanined.—In the dried state. I received the sponge under consideration from my late friend, Mrs. Buckland, who obtained it at Guernsey, with other British species, n 1857. The specimen is not entire, one end and a portion of one side having been cut away for examination. From its present aspect it does not appear to have exceeded an inch and a quarter in length by half an inch in breadth, and the same in height; and it seems to have been adherent by nearly the whole of its under sur- face. In its general aspect it closely resembles 7. Collingsit. The dermis is very thick and dense, in consequence of the profusion of the ternate terminations of the connecting spicula which are crowded over each other, forming a dense and strong crust to the sponge. The dermal membrane is thin and pellucid, and is abundantly furnished with spinu- late tension spicula irregularly dispersed on its surface, iuterspersed with which there are both forms of the stellate retentive spicula, but not in any great number; while in the membranes of the intermarginal cavities, and in the interstitial membranes beneath, they are in profusion. The intermarginal cavities are disposed between the dermal membrane and the distal stratum of the ternate termina- tions of the connecting spicula, the fasciculi of which diverge BRITISH SPONGIADA. 91 from their junctions with the skeleton fasciculi beneath, and meeting each other at their distal portions, form a uniform and continuous surface for the support of the intermarginal cavities. The external defensive spicula are rather nu- merous. In the dried condition of the sponge they are projected about half their length through the dermal mem- brane; the bulbous bases of these spicula are strongly produced, the shafts are often long and flexuous, and occa- sionally they are sub-fusiform. Although these spicula are so abundant in the dermal and intermarginal membranes, I could not detect them in the deeply seated interstitial ones, while the same tissues were crowded with both forms of stellate retentive spicula. The attenuato-stellate spicula are three or four times the diameter of the cylindro-stellate ones, and frequently have not more than five or six rays, while the latter have usually ten or twelve rays. ‘This species, in its habit and structural peculiarities, closely resembles 7. Collingsit. The skeleton and connecting spi- cula are of the same form in each, but those of the skeleton in 7. Schmidtit are shorter, ‘and less in diameter than those of Z. Collingsii. The connecting spicula of the former are also shorter and stouter than in the latter species, but although thus less in size they have the ternate terminations much larger than in Z Collingsii. Thus the differential characters of the two species are not readily apparent to a hasty investigator, but by a more minute examination when mounted in Canada balsam, with the aid of a microscopical power of about one hundred linear, and by a close obser- vation of the dermal spicular characters, the two species may be readily distinguished. ; I have named this species after Dr. Oscar Schmidt, Professor of Zoology in the University of Gratz, who has done so much to advance our knowledge of the European species of sponges, by the publication of his valuable work on the sponges of the Adriatic. (‘ Die Spongien des Adria- tischen Meere.’) A specimen of this species was found between two stones, at extreme low-water mark, by the Rev. A. M. Norman, 1865. 92 A MONOGRAPH OF THE 4. TetHea Lyncurium, Johaston. ALCYONIUM LyncURIUM, Linneus. Sponge. Massive, globular, sessile. Surface smooth and even. Oscula and pores inconspicuous. Dermis thick and coriaceous; furnished abundantly with large sub- sphero-stellate spicula with acutely conical radii, and near the external surface with numerous minute attenuato-stellate spicula. Skeleton. Spicula fusiformi- acuate, large and long, fasciculated into long stout bundles, which expand greatly at their distal corym- bose terminations. Interstitial membranes furnished abundantly with long, slender, fusiformi-acerate tension spicula, dispersed in lines radiating from the centre of the sponge towards the inner surface of the dermis, and with numerous minute attenuato-stellate spicula. Gemmules. External, pullulating from near the base of the sponge; spicula, same forms as those of the parent. Colour.—Alive, dull orange, to bright chrome yellow. Hatitat.—Plymouth, Mr. Thomas Howard Stewart ; Torquay, Dr. Battersley and Mr. Gosse; Guernsey, Mrs. Buckland; Diamond Ground, off Hastings, J. S. Bowerbank ; thirteen fathoms off Tremain Bay, Guernsey, Rev. A. M. Norman. Ezxamined.—In the living state. The general external characters presented to the un- assisted eye are accurately described by Dr. Johnston, in his ‘History of British Sponges,’ p. 85, but the warted appearances represented by Figs. 12, a, 4, p. 87, are~not strictly natural. ‘This character has been produced by the corymbose terminations of the large radial skeleton fasciculi remaining stationary, while the surrounding coriaceous and BRITISH SPONGIADZ. 93 softer tissues of the sponge have been more or less con- ‘tracted by either immersion in spirit or by drying. In several living specimens which I have obtained im- mediately after they had been taken from the sea, the surface was smooth and not at all hispid, and the terminations of the radial fasciculi of the skeleton which form the wart-like projections in the specimens preserved in spirit or dried, were scarcely visible in the living ones. The oscula are not usually visible, but in one specimen of the sponge sent to me by Dr. Battersley, enveloped in wet seaweeds, in a small jar, on immersing it in fresh sea-water, after about an hour I observed several oscula open near the distal end of the sponge; on probing one of them with a fine grass straw, the whole slowly closed, and I did not again succeed in seeing them open, but this event sufficiently indicated their locality. The diameter of the largest of the open oscula was rather exceeding a line. The dermal crust of the sponge varies from one to two or two and a half lines in thickness. It appears to be thickest on the upper half. of the animal, and especially at the extreme horizontal circumference, and the lower half is frequently not above half the thickness of the upper one. The large subsphero-stellate spicula are abundantly dis- persed in the coriaceous substance of the dermis between the expanding terminations of the distal extremities of the skeleton fasciculi, and the small attenuato-stellate spicula are very abundant on the inner surface of the dermal mem- brane, and immediately beneath it, as if designed to especially protect it from the attacks of small predacious enemies which may have located themselves on its surface. The large corymbose expansions of the distal termina- tions of the skeleton fasciculi are produced by the addition of a great number of fusiformi-acuate spicula, not above one third or half the size of the proper skeleton spicula ; they are intermingled with the larger ones, without any apparent order, and their distal terminations are in accordance with those of the primary skeleton ones. I am indebted to my late friend, Mr. Thomas Howard Stewart, of the Royal College of Surgeons, a promising 94 A MONOGRAPH OF THE young naturalist, whom we have lost in the prime of his intellectual development, for my first knowledge of the mode of external development of the gemmules of this species. He found them pullulating from near the base of a specimen of the sponge which he obtained in the neigh- bourhood of Plymouth; and subsequently, on the 26th of January, 1862, I found six of the gemmules around the base of a living specimen which was dredged at the Diamond ground, off Hastings. The parent sponges and the gem- mules in each case very closely resemble each other. Each of the gemmules was attached to the parent sponge by a fasciculus formed of several skeleton spicula; the bodies of the gemmules were quite separated from the Tethea, and each gemmule had its own distinct groups of radiating spicula. I have never succeeded in finding internal gem- mules in any specimen of the sponge in which I have searched for them. 5. TErHEA SPINULARIA, Bowerbank. Sponge. Massive. Surface even, minutely hispid. Oscula terminal, slightly elevated. Pores inconspicuous. Der- mis coriaceous, thick. Dermal membrane pellucid, furnished at intervals with fasciculi of minute acerate spicula ; spicula of the fasciculi very numerous, slightly curved, disposed parallel to each other, with the curves in accordance. Skeleton. Spicula subfusiformi-ovo- spinulate, long, and rather stout. External defensive spicula continuations of the skeleton fasciculi. Dermal defensive spicula fusiformi-ovo-spinulate, short and stout, disposed at right angles to surface, very nu- merous. ‘Tension spicula sub-fusiformi ovo-spinulate ; as large as those of the skeleton, irregularly dispersed, numerous ; and also fusiformi-acerate, fasciculated like those of dermal membrane ; fasciculi few in number. Colour.—Dried, gray, with a tint of green. Habitat—Shetland, Rev. A. M. Norman. BRITISH SPONGIADA. 95 Examined.—In the dried state. I received six specimens and a fragment of this species from the Rev. A. M. Norman, who obtained them at Shet- land. They were all nearly circular, and much depressed ; they varied in diameter from three to seven lines, and the greatest height did not exceed three lines. In the middle of the upper surface of each there is one or more slightly elevated mammz, and some of them presented rather indistinct indications of a closed osculum at their summits. The marginal portions of the specimens were covered with fine sand, which adhered strongly to the surface, but the mamme, and immediately around them is clean, and free from it, probably by the action of the excurrent streams of water from the oscula. None of the specimens possessed the natural base, and the whole of them appeared as if they had been removed by a knife from the surface of a flat shell or stone. In the depressed form this species harmonises in habit with 7. Collingsii. At the edge of the largest specimen a young 7. cranium, scarcely exceeding a, line in diameter, has fixed itself, as if to bear testimony to its Shetland locality. The minute hispidation of the external surface is scarcely visible by the aid of a lens of one inch focus. When soaked in water the sponge appeared to be very firm and strong, and a section of the dermis in the dried condition presented very much the same texture and appearance as a slice from the margin of a thin white card. - The terminations of the skeleton fasciculi forming the external defensive system, project about half or two thirds the length of a skeleton spiculum beyond the dermal surface, but those of the secondary system or dermal defensive spicula, rarely pene- trate the dermal membrane. They are extremely numerous, and very closely packed together, their apices appearing immediately below the dermal membrane, and the bases of the largest and longest of them reaching to the inner sur- face of the coriaceous dermis. In the general character of form they closely resemble the skeleton spicula, but differ from them in being very much shorter, stouter, and more 96 A MONOGRAPH OF THE fusiform in their proportions. The skeleton spicula are comparatively long and large, and slightly fusiform, and the form of their spinulation is very peculiar, the bulbous base being oviform, the distal portion being the smallest. This character appears to be a very constant one, and appertains to the dermal defensive spicula as well as to the skeleton ones. The large tension spicula strengthen and support the interstitial tissue most effectively ; they cross the skeleton fasciculi and each other in every possible direction, and are very numerous. The smaller description of tension spicula are very slender and delicate in their proportions, and are closely packed together in a fasciculus that rarely exceeds the length of one of the spicula. The fasciculi are irregu- larly dispersed on the interstitial membranes ; two or three fasciculi are occasionally found together. Genus—Haticnemia, Bowerbank. 1. Haticnemr1a PATERA, Bowerbank. Sponge. Circular, concavo-convex, very thin; sessile, radiating from a small pebble imbedded in its centre. Upper surface convex, hispid by the projection of nu- merous bundles of long, slender, acerate defensive spi- cula ; fasciculi radiating from the centre to the sur- face, and to the circumference, where they form a deep marginal fringe. Lower surface concave, smooth, and even. Oscula simple, dispersed on the lower surface, numerous and minute. Pores inconspicuous. Der- mal membranes pellucid, spiculous; spicula very numerous, dispersed, fusiformi-acerate, entirely spined, subangulated, and frequently inflated at the middle. Skeleton. Spicula, attenuato-spinulate and fusiformi- spinulate, short and stout; and spinulate long and BRITISH SPONGIADA. 97 large; spicula frequently with one or two extra infla- tions near the basal one. Interstitial membranes. Tension spicula abundant, the same in form as the dermal ones. Colour.—Dried, light gray. Habitat——Shetland, Deep sea, Mr. Barlee, and Rev. A. M. Norman, 1863 ; Unst, Shetland, Mr. C. W. Peach, 1864. Ezamined.—In the dried state. The first specimens I received of this sponge were from my friend the late Mr. Barlee, who dredged them, I believe, in about 70 fathoms, off Shetland. The greatest diameter of the large specimen is one inch, that of the smaller one three quarters of an inch. The height of the large specimen is about a quarter of an inch, and its greatest thickness about one third of a line. There is a considerable amount of extraneous matter de- posited on the upper or convex surface of each of the sponges ; and the concave, or underside of each, appears perfectly clear from such impurities. The only attachment in both of these specimens is to the small pebble imbedded in its centre, and the species is evidently not stationary, as in the larger specimen, with the concave surface downward, the central stone does not touch the plane surface on which its marginal fringe rests, and the under surface of the pebble in each is partially covered by a thin stratum of spongeous matter. The upper surface of the pebble in both is entirely covered by the dermal tissue of the sponge. This accordance in habit seems to indicate that the natural position is with the concave surface downward, and its freedom from impurities on that surface is the natural result of the action of the excurrent streams from the oscula which abound at the margin of the concave surface of the sponge. ‘Ihe habit of the sponge of in- cluding a small pebble in its centre, apparently as ballast, is very remarkable, and this is the only case in —e there 98 A MONOGRAPH OF THE is an indication of a natural tendency to locomotion belong- ing to the adult species that I have ever observed among the Spongiade. The oscula were most numerous and largest near the margin of the under surface, and a few only were apparent on the upper surface of the smaller specimen. The greater number of the pores were closed; a few that were open on the upper surface of the larger specimen were very minute when viewed with a power of one hun- dred linear by direct light. The dermal membrane on both surfaces is crowded with its peculiar spicula. They are singular in their form, being fusiformi-acerate, not curved as is usually the case with such spicula, but bent abruptly near the middle of the shaft, so as to form more or less of an angle, and at or near this spot there is generally an inflation of the shaft. The adult spicula are profusely and entirely spinous, but when not fully developed they are frequently quite smooth, or have the spines but very faintly indicated, but although not fully developed they are rarely without the inflation at or near the angle. The skeleton spicula are remarkably large and very variable in form and proportions. The large, long, spinu- late form, with one or two extra inflations, near the base of the shaft, are all disposed in one thin stratum, about midway between the upper and lower surfaces of the sponge, the bases being all towards the centre, and their points radiating towards the circumference. The short, stout, attenuato-spinulate and fusiformi-spinulate ones, with occasionally one extra inflation near the base, are mixed together, without order, in a thick stratum, which occupies the space between the stratum of long spinulate spicula and the lower surface of the sponge. The interval between the central stratum and the upper surface is occupied by large cavernous spaces which communicate by orifices in the interstitial membranes, which are abun- dantly furnished with tension spicula dispersed on their surfaces. Numerous hollow, irregular ridges or cones of dermal membrane are projected from the upper surface of BRITISH SPONGIADA. 99 the sponge, and these are frequently terminated with a fasciculus of long, slender, acerate, defensive spicula. ‘lhe marginal fringe of the sponge is formed by a continuation of the central stratum of large spinulate spicula slightly beyond the solid margin of the sponge, and by the addition of numerous long, acerate, defensive spicula. The inter- stitial membranes are thickly covered with sarcode, in which there are numerous minute granulated vesicles. Since the above description was written I have received two specimens for examination from the Rev. A. M. Norman, who dredged them at Shetland in 1863. One was nine lines and the other seven lines in diameter and each had a small pebble imbedded in its centre, and in every other respect they closely resembled the specimens described. Two other specimens, dredged in the same locality, in 1864, were sent to me by my friend Mr. C. W. Peach ; the diameter of one specimen was one inch, and of the other seven lines. The central pebble in neither of these specimens was visible but its presence was indicated by a slight projection near the middle of the concave sur- face of each, and on probing these spots with a sharp needle their impenetrability gave assurance of its presence. From the size of Mr. Peach’s largest specimen being the same as the large one from Mr. Barlee, it is probable that the greatest diameter of this species rarely exceeds one inch. 100 A MONOGRAPH OF THE Genus—DicrvocyLinprus, Bowerbank. Sxetron * Skeleton spicula, acerate and acuate. 1. Dictyocylindrus ventilabrum, Bowerbank. 2. — TAMOSUS, Bowerbank. 3. —_ radiosus, Bowerbank. Section * * Skeleton spicula, acuate. 4, Dictyocylindrus Howset, Bowerbank. F — hispidus, | Bowerbank. — aculeatus, | Bowerbank. — fascicularis, Bowerbank. — virgultosus, Bowerbank. OS Section * * * Skeleton spicula, spinulate. 9. Dictyocylindrus pumilus, Bowerbank. Section * * * * Skeleton. spicula, cylindrical. 10. Dictyocylindrus stuposus, Bowerbank. 11. — rugosus, Bowerbank. 1. DicryocyLINDRUS VENTILABRUM, Bowerbank. Sponge. Pedicelled, ramose, fan-shaped ; surface hispid ; branches dividing dichotomously, rarely trichotomously. Oscula and pores inconspicuous. Skeleton. acuate and acerate, elongate, often flexuous. External defensive spicula attenuato-acuate, long and _ stout. Tension spicula fusiformi-acuate or acerate, slender. Internal defensive spicula attenuato-acuate, entirely but minutely spined. Colour.—Alive, bright orange yellow. Buff yellow in the dried state, BRITISH SPONGIADA. 101 Habitat.—British Channel, Brighton, Mr. Beckles. Ewamined.—In the dried state. For this remarkable sponge I am indebted to the kind- ness and liberality of Mr. Samuel H. Beckles, of St. Leonards, who states, “I obtained it at Brighton ; it was brought in by a fishing-boat, and is the only piece of the kind that I have ever seen.” : The pedicel is barely an inch in height; at an inch and a half from the base it has divided into four primary branches ; within an inch from their origin these primary branches each divide dichotomously, and this mode of division continues, with a single exception of one branch dividing trichotomously, so that at four inches from the base there are as many as twenty-two, all nearly in the same plane, assuming a fan-shaped series of branches, eight inches in height by about the same extent in width. ‘lhe branches are cylindrical, or very slightly compressed; be- side those produced by dichotomous division there are a few slender ones, thrown off irregularly, but laterally from the principal branches. In the dried condition of the sponge the hispid character is remarkably striking, the fasciculi of radiating spicula projecting from the central cylinder of the skeleton to the extent of at least one third of the whole diameter of the branch; but it is probable that in a living state their apices would be barely visible beyond the dermal membrane, no portion of which remains attached to the sponge, but portions of the sarcode and interstitial membranes are still found im situ, near the apices of the radiating spicula, in which there are numerous slender, fusiformi-acuate tension spicula belonging to the membranes, collected in loose fasciculi, which each contain a considerable number of these spicula. The internal de- fensive spicula of the skeleton are not very numerous ; they are slender in their proportions compared with the like description of spicula in other sponges, nor are the spines very strongly produced. Montagu’s Spongia ramosd, de- scribed as “ palmated and digitated round the top,” and said to have been “first noticed in Mr. Boyer’s cabinet of 102 A MONOGRAPH OF THE British shells,” appears to be the species so abundant near Hastings, and designated Dictyocylindrus ramosus in this work, while the sponge to which he alludes when he writes, | have since taken a larger and more perfect specimen on the coast of Devon, measuring nearly five inches in height,” is possibly the species now under consideration, but if the figure given by Montagu, plate vii, vol. Hi, ‘ Wernerian Memoirs,’ represents that sponge, it has evidently been in a very dilapidated condition; what remains of it would agree very well in size and form with the corresponding portion of Mr. Beckles’ specimen, but in other respects the identification is far from complete ; I have therefore thought it advisable to consider D. ramosus of this work as the type of Montagu’s Spongia ramosa, and to give a distinct name to Mr. Beckles’ specimen. I may also observe that D. ramosus has been obtained from the Brixham trawlers by my friend Mr. ‘Thomas Ingall, exceeding nine inches in height. Since the above was written, I have obtained a second specimen of this species from Mr. Henry Ridley, who states that it was taken by a trawler on the Rough Ground between Hastings and Brighton, early in May. When he received it, it was of a bright orange-yellow colour. This specimen does not exhibit the same fan-shaped outline, and numerous branches, that exist in the type specimen. It has the same short pedicel, and commences branching an inch from the base in the same manner, but it has only three branches; the first of them attains the height, in- cluding the basal portion, of ten and a quarter inches; the second branch divides dichotomously at about three inches from the base, and neither of these two exceed five and a half inches in height, and all are in the same plane, and the branches near their origin have the same description of slender lateral branches that are observable in the larger specimen. The colour of Mr. Beckles’ specimen was stated by the person who had the sponge from the fisherman to have been darker and more yellow before it was dried; it harmonises in colour, therefore, very closely with the specimen I obtained: in ‘the fresh state from Mr. Henry Ridley, of Hastings. BRITISH SPONGIADA. 103 2. DicrYocyLInDRUS RAMOSUS, Bowerbank. Sponeia Ramosa. Gerard’s Herbal emended, 1577, No. 9. —_ — Montagu. Wern. Mem., vol. ii, p. 84, pl. viii. — cristata, Montagu. Haricnonpria RaMosA, Johnston. Hist. British Sponges, p. 99. Sponge. Arborescent, pedicelled, branches palmate, digi- tate, or irregular ; cylindrical or compressed. Surface smooth and fleshy when alive. Oscula and pores in- conspicuous. Dermal membrane pellucid, aspiculous. Skeleton. Spicula of axis sub-fusiformi-acuate, rarely _cylindrical ; radial spicula same as those of the axis, large and long. Internal defensive spicula; attenuato- acuate or sub-spinulate, numerous; spines minute. Tension spicula fusiformi acerate and acuate, slender, and often flexuous, numerous. Gemmules, membra- nous, aspiculous. Colour —Alive, yellow, orange, flesh-colour, pink or crim- son. Light to dark brown in the dried state. Locality.—South coast of England, rather common, Mr. Tumanowicz ; Guernsey, and Polperro, Cornwall, Rev. A. M. Norman; Torquay, Mr. Thomas Ingall; Rye, Brighton, and Sark, J. S. Bowerbank. Ewamined.—In the living state. This species is subject to considerable variation in its form. I have obtained a great number of specimens from the neighbourhood of Hastings, where it is frequently found at high-water mark on the beach; very few of them exceed three inches in height, and they vary considerably in form and in the modes of the disposition of their branches. In some cases they ramify in every possible direction, while in others they assume a palmate or digitate arrangement. In the latter two forms of growth the branches are frequently much compressed. = 104 A MONOGRAPH OF THE My late friend Mr. Thomas Ingall obtained specimens of this species from the trawlers at Brixham, near ‘Torquay, of very much greater size than any I have seen from Hastings and its neighbourhood, some of them having a height and breadth of nearly ten inches. The branches of these specimens were nearly all in the same plane; few in number, comparatively slender, and gradually attenuating to their distal extremities. Although differmg so much in size, form, and proportions, from the Hastings’ specimens, no organic differences could be detected. - Mr. Tumanowicz, of Hastings, has found this sponge alive after severe storms during the winter, and in this state he informs me that they are of a light orange-yellow colour, and that the lateral spicula rarely project beyond the external surface, excepting near the apex of the branch, and then to no great extent. Specimens subsequently found by the same gentleman were some of them deep crimson, with a slight shade of brown. When dried, this species presents a widely different aspect to that of the living spe- cimens; in the latter state it is smooth and fleshy, in the former it is dark brown, and is profusely and strongly hispid. The dermal membrane has no peculiar spicula, but a few of the tension spicula common to the whole of its internal membranes may be seen dispersed on its inner surface. The internal defensive spicula vary considerably in size; they are very numerous, and three or four of them are often grouped together on the skeleton tissues. The only specimen in which I have found the gemmules was sent to me for examination by the Rev. A. M. Norman, who obtained it at Polperro, Cornwall. There is little doubt that this species is the one desig- nated Spongia ramosa by Gerard in his ‘ Herbal,’ emended by Johnston, and by Montagu in the ‘ Wernerian Memoirs.’ The description by the latter author of the manner in which it splits, and divides into fascicles, is correct as applied to a weather-worn specimen, but not to an unmutilated one. The specimen in Montagu’s collection of sponges, in the possession of Professor Grant, of University College, labelled BRITISH SPONGIADS. 105 S. cristata, is a very young specimen of our D. ramosus, possessing none of the adult characters of that species, but agreeing with it precisely in the mode of arrangement, and in the form and proportion of the spicula of the skeleton, and of the internal defensive ones also. The form of the specimen has evidently misled Montagu, and induced him to believe it was of the same species as Ellis’s 8. cristata, which is certainly one of the many varieties of Halichondria panicea found abundantly on the reefs of rocks off Hastings that are submerged excepting at low water. 8. DicryocyLinDRus RADIOSUS, Bowerbank. Sponge. Pedicelled, branching dichotomously in nearly the same plane, compressed. Surface even, hispid. Oscula simple, dispersed, minute. Pores inconspi- cuous. “Dermal membrane spiculous, tension spicula acerate, long, and extremely slender, often flexuous, dispersed or loosely fasciculated. External defensive spicula congregated in distinct and separate radiating fasciculi, nearly equidistant ;-spicula large and long. Skeleton. Axial spicula acerate and acuate, stout, and very long. Interstitial membrane spiculous ; spicula same as those of the dermal membrane, rather numerous. -Colour.—Dried, nut-brown. Habitat—Vazon Bay, Guernsey, Mr. Cooper. Examined.—In the dried state. I am indebted to my friend the Rev. A. M. Norman, for my knowledge of this sponge, he received it, with other interesting specimens, from Mr. Cooper, of Guernsey, in 1865. It is two and a half inches high, and three inches in width; it has not its natural base. At seven lines above its present base it divides into two principal branches, and it continues to subdivide dichotomously at unequal dis- tances to near the distal terminations of the branches, 106 A MONOGRAPH OF THE which are all more or less furcate. All the branches are compressed, and they occupy nearly the same plane. The hispidation is strikingly characteristic in this sponge; the whole surface is furnished with numerous radiating fasciculi of large and long acuate spicula; each group contains from six to about ten spicula, diverging from each other at small angles, so that the whole combined present a regular series of defensive points at a slight distance beyond the dermal surface, while the bases of the groups are widely and dis- tinctly separated from each other; the spicula are stouter and stronger than those of the skeleton. The axial column of the sponge is comparatively large ; it extends very nearly to the dermal membrane. The skeleton spicula, acerate and acuate, are indiscriminately mixed in the structure, both are long and slender in proportion to their diameter, the acerate rather preponderating in number. From its size, form, and general aspect, this species may readily be confounded with D. stuposa by a hasty observer, but the total absence of stellate spicula in the dermal mem- brane distinguishes it at once from that species. The general habit of D. fascicularis, end the species under consideration, are so like each other that those who are not acquainted with both species might be apt to confound the two, by the description of the external characters only, but here, again, a microscopical examination of either species will quickly relieve us from this chance of error. 4, Dicryocytinprus Howse1, Bowerbank. Sponge. Arborescent, pedicelled ; branching dichotomously or trichotomously ; branches slightly compressed, his- pid ascendingly, surface smooth (?). Oscula and pores inconspicuous. Dermal membrane pellucid, aspicu- lous. Skeleton. Spicula sub-fusiformi-acuate, often sub-spinulate, large. External defensive spicula same as those of skeleton, large and long. ‘Tension spi- cula abundant. Acuate, rarely acerate, slender, and often flexuous ; disposed in irregular, broad fasciculi. BRITISH SPONGIADS. 107 Internal defensive spicula, entirely spined, sub-clavated attenuato-acuate, very few in number. Colour.—Alive, scarlet ; dried, light brown. Hatitat.—Douglass Bay, Isle of Man; Strangford Lough, Treland, Dr. Dickie. Ihave seen but two specimens of this species, and neither of them were in a perfect state of preservation. I am in- debted to Mr. Howse, of Newcastle, for my first knowledge of it. He kindly sent me for examination three small pieces, the largest not exceeding two inches in length. I subsequently received a specimen from Dr. Dickie, un- fortunately also broken into pieces; the largest fragment was about two inches long, branching dichotomously, and based on a valve of a small bivalve shell covering a con- siderable portion of its surface, and from this spreading base, four branches appear to have sprung. The skeleton spicula vary considerably in size, many of them are very stout and long; the fusiform character is but slightly developed, and about half of them exhibit more or less traces of spinuldtion ; the remainder are acuate, with occasionally an acerate one. The external defensive spicula are of the same form as those of the skeleton, but rather larger in size. ‘Their position in the sponge is very cha- racteristic of the species. I could not detect the internal defensive spicula ia situ in either of the specimens, but among those obtained from boiling in nitric acid a portion of one of the fragments sent to me by Dr. Dickie, there were a few entirely spined sub-clavated, attenuato-acuate spicula, agreeing perfectly with each other in their cha- racters, thus affording an indication of their presence in the sponge, although they could not be detected in the portions I examined. I have dedicated this species to Mr. Howse of New- castle-on-Tyne, in acknowledgment of the good service he has rendered to science in this and in numerous other instances. 108 A MONOGRAPH OF THE 5. DicryocyLinpus HisPipus, Bowerbank. Sponcra HISPIDA, Montagu. Wern. Mem., vol. ii, pl. v, figs. 1 and 2. HALICHONDRIA HISPIDA, Fleming and Johnston. Sponge. Pedicelled, arborescent; branches long and slender, dividing dichotomously, or trichotomously. Surface smooth, somewhat hispid. Oscula and pores inconspicuous. Dermal membrane pellucid, 'aspicu- lous. Skeleton. Spicula acuate, large and long, rarely acerate. External defensive spicula same as those of the skeleton. Internal defensive spicula, attenuato- acuate or sub-spinulate, entirely spined; few in number, spines conical; acute and rather minute. ‘Tension spicula acuate and acerate, long and very slender. Colour.—Alive, yellow or orange. Habitat—Coast of Devonshire, Professor Quekett ; Pol- ‘perro, Cornwall, Rev. A. M. Norman ; Diamond Trawling Ground, Hastings, J. 8. Bowerbank. Exwamined.—tin the living or fresh state. I have obtained several good specimens of this species from the Diamond Trawling Ground off Hastings, by the aid of Mr. H. Ridley. Montagu’s description of the sponge in the dried condition is good as far as it goes. In this state it is remarkably hispid, but when fresh the sarcode is so abundant that very few, comparatively, of the long external defensive spicula are projected beyond the dermal membrane. The specimen described by Montagu as being attached by its side, and branching at both ends, is evidently an abnormal form of attachment and growth. All that I have seen, rise, as he states, “‘ perpendicular from ~ the base,” which is generally slightly expanded and firmly attached to a stone or shell. In the recent condition it is soft and flexible. The sarcode is very abundant, and in some specimens it abounded in nucleated cells which BRITISH SPONGIADA. 109 required a microscopic power of about 300 linear to define them well.. I could not detect the oscula in any of the specimens I examined. Among the specimens of British sponges formerly be- longing to Colonel Montagu, but now in the possession of Professor Grant, there is a dwarf specimen of this species, but it is not the type one figured by Montagu in vol. ii, pl. 5, of the ‘ Wernerian Memoirs.’ 6. DictyocyLinpRrus acuLeatus, Bowerbank. HaticHoNnDRIATA ACULEATA, Johnston. Sponge. Sessile, rising from numerous small slightly expanded bases, branching and anastomosing. Sur- face uneven, abundantly furnished with large spicula projecting at nearly right angles to the axis. Oscula and pores inconspicuous. Dermal membrane pellucid, somewhat stout. Spicula. Of the skeleton; acuate, large, long and flexuous. Of the membranes; fusifor- mi-acerate and occasionally fusiformi-acuate; slender and flexuous. Internal defensive spicula attenuato- acuate, slightly but entirely spined, rare. Gemmules? Spherical or slightly oval, smooth, opaque, from once to twice the largest diameter ofthe skeleton spicula. Colour.—Purple-gray when dried. Habitat.—Scarborough, Mr. Bean. Examined—lIn the dried state. This interesting little species was found at Scarborough, many years since, by my indefatigable friend, Mr. Bean. He had labelled it Halichondria aculeata in his cabinet. I have therefore adopted that appropriate specific name. -The height of the sponge does not exceed half an inch, and its numerous primary branches are based on small Balani; they are all nearly equal in height, and at their distal extremities there are occasionally branches thrown off in a horizontal direction, which seems to indicate that 110 A MONOGRAPH OF THE the sponge had attained about its greatest altitude. In height and general habit it may readily be mistaken for Halichondria Hyndmanii, but the branches do not ter- minate in a corymbose manner, as in that species. In the dry condition the projection of the surface spicula is nearly equal to the diameter of the primary branches. In the dried state the surface is irregularly and deeply excavated, but it is probable that this character would not be apparent in the living sponge. The spicula of the skeleton are somewhat irregular in structure ; the normal form is regularly acuate and flexuous, but occasionally they are sub-spinulate or sub-cylindrical ; the distal termination is usually gradual and regular, but sometimes it is much attenuated and at others abrupt, and in the latter case it is often more or less mucronate. The internal defensive spicula are very few in number, and are not to be readily found, either zw situ or after the separation of the spicula in boiling nitric acid; occasionally they are subspinulate. The opaque gemmular bodies are dispersed irregularly amidst the tissues, sometimes appearing attached to the spicula, but more frequently slightly imbedded in the sur- face of the interstitial membranes; they have the appear- ance of a transparent: integument, comparatively thick, enclosing an opaque, dark, steel-gray coloured nucleus. I could not discover any indication of spicula belonging to the integument, either i situ or after treatment with boiling nitric acid. 7. DICTYOCYLINDRUS FASCICTLARIS, Bowerbank. Sponge. Arborescent, slender; branches cylindrical, di- viding dichotomously. Surface smooth, aspiculous. Oscula and pores inconspicuous. Dermal membrane simple, translucent, aspiculous. Skeleton. Dense, abundantly spiculous; spicula attenuato-acuate, slen- der, often flexuous; furnished with distinct radiating fasciculi of external defensive spicula; spicula of the BRITISH SPONGIADA. 111 fasciculi attenuato-acuate, stouter than those of the skeleton. Sarcode abundant, furnished sparingly with minute stellate spicula. Colour.—Light amber when dried. Habitat.—Hastings, Mr. Tumanowicz; Diamond Trawl- ing Ground, Mr. H. Ridley; Guernsey, Miss Le Lievre ; Vazon Bay, Guernsey, Mr. Cooper. EHaamined.—In the dry state. I received the first specimen of this sponge from Mr. Tumanowicz, of Hastings, who informed me that it was found on the beach in the neighbourhood. . The specimen is unfortunately imperfect, having been broken off, probably, about half an inch above its natural base. In its present condition it is two and a half inches long, and about a line in diameter. The principal stem is nearly straight, and at half an inch from the lower end it throws off a single curved branch rather less than an inch in length, from which a second very small branch is given off in like manner. The sponge is so similar in size and proportion toa slender specimen of Dictyocylindrus stuposa, dredged. at the Orkney Islands by Mr. McAndrew, that at first sight I concluded that it must belong to that species, but on examining it with a lens of an inch focus the unu- sually corrugated and wasted appearance of the surface induced me to investigate it more closely. When viewed beneath a power of one hundred linear by direct light, each of the minute elevations’ is seen to be produced by the projection of a dense radiating bundle of spicula more or less enveloped in sarcode, thus presenting an appearance of a series of wart-like elevations on the surface of the dried specimen, but which would not, most probably, exist on the surface of the sponge when in the living and fully expanded condition. On examining a longitudinal section of the stem of the sponge through the centre of the axis, in water, as a transparent object, with a linear power of one hundred and sixty, the fasciculi of spicula were seen based on the cylindrical axis of the skeleton, and radiating thence through the thick coat of sarcode, to the surface, and to 112 A MONOGRAPH OF THE a slight extent beyond it. ach of the fasciculi consists of a great number of spicula, and the radiation is frequently to such an extent as to form an angle of twenty or thirty degrees. In the spaces intervening between the fasciculi there is very rarely even a single spiculum to be seen passing from the axis of the sponge to its surface. I could not separate the dermal membrane from the mass of sarcode beneath it, but it is evidently thin, simple and transparent, and apparently destitute of spicula. The thick cylinder of sarcode surrounding the axial skeleton is uniform in its texture, and without any appear- ance of cavities or canals, and there are thinly and irregu- larly scattered through the whole of its substance, a few stellate spicula, with about six or eight attenuating radii. These spicula are very minute, not exceeding goth inch from point to point of the radii, and require a power of about 600 linear to exhibit them in a satisfactory manner. The axial skeleton of this species is more complex in its structure than that of many of the allied species. The spicula of which it is composed are very slender, frequently flexuous and very numerous. Although at first sight this species may be readily confounded with slender specimens of D. stuposa, its anatomical differences readily distinguish it from that sponge. I subsequently obtained from Mr. Henry Ridley, of Hastings, a much larger specimen of this sponge, it rather exceeded eight inches in height; like the first specimen, it had not the natural base, but the lower portion of the stem was two and a half lines in diameter. In every other cha- racter, except the size, it closely resembled the specimen I received from Mr. Tumanowicz. Although a more mature and much larger specimen than the type one and in a per- fectly dry condition, I could not detect any protrusion of spicula through the dermal membrane. In this specimen, and in one obtained by the Rev. A. M. Norman from Mr. Cooper, of Guernsey, the whole of the branches are deve- loped in the same plane; but in the specimen presented to Mr. Norman by Miss Le Lievre this is not the case, but the latter specimen has the appearance of having been dis- BRITISH SPONGIADA. 113 .torted in the course of its growth, and the branches have united where they have touched each other. ‘The warted appearance of the surface is very strongly produced in Mr. Cooper’s specimen, but in the other two referred to it is not nearly so apparent, in consequence of the peripheral fasci- culi being so numerous and so close to each other as to almost obscure their fascicular character. Mr. Cooper's specimen has the natural base, which does not spread to a greater extent than about twice the diameter of the prin- cipal stem of the sponge. This species does not appear to attain a great size; the largest specimen I have seen is four and a half inches high and four inches broad, and the principal stem does not exceed one fifth of an inch in diameter. 8. DicryocyYLINDRUS VIRGULTOSUS, Bowerbank. Sponge. Sessile, virgultose; branches simple, ascending, very spinous. Oscula simple, dispersed. Pores in- conspicuous. Dermal membrane pellucid, aspiculous. Skeleton: spicula acuate or attenuato-cylindrical, large and long, rarely subclavate. External defensive spicula, primary series, acerate or fusiformi-acuate, short and slender, very numerous, fasciculated, diver- gent. Internal defensive spicula subclavate, attenuato- acuate, entirely spined, variable in size, occasionally very large and long; spines conical, minute. Colour.—Dried, dark greenish-gray. Habitat.—Shetland, Rev. A. M. Norman. Famined.—In the dried state. I received nine specimens of this sponge from the Rev. A. M. Norman; none of them exceeded an inch in height. The body of the sponge is irregularly massive and sessile ; at about a quarter of an inch from the base it divides into a number of upright, straight, attenuating branches, which appear never to subdivide or dichotomise. Very few of 8 114 A MONOGRAPH OF THE them exceed a line in diameter at the base, and they gra- dually attenuate to their distal terminations. When held up to the light they appear profusely spinous, the spi- cula projecting at right angles to the surface, frequently to the extent of two or three times the diameter of the part of the branch whence they spring. The branches all attain to nearly the same height, and their terminations are fur- nished with numerous large defensive spicula, which are - projected in lines nearly in accordance with the axis of the branch, : From the appearance of the dried specimens it is pro- bable that in the living condition the diameter of the branches would be at least twice that of their present con- dition. The secondary external defensive system consists of numerous fasciculi of comparatively small, slender, acutely terminated spicula, diverging from the base of the fasciculus, and spreading in every possible direction. The internal defensive spicula are very numerous, and are ex- ceedingly various in size. Many of them are abruptly curved near the base, and the clavate expansion at the base of the gréater portion of them is excentric to the axis of the spiculum. 9. DicryocyLinpRus puMILUS, Bowerbank. Sponge. Sessile, or very slightly elevated on a massive pedicle; branching dichotomously ‘or trichotomously ; branches short, stout, obtusely terminated. Surface very slightly hispid in the living state. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane pellucid, aspiculous. Skeleton: spicula of axis sub-spinulate or acuate, rarely enormi-spinu- late; radial spicula same as those of the axis. In- ternal defensive spicula attenuato-acuate or sub- spinulate, entirely spined. Tension spicula acuate or acerate, long and slender. Colour.—Alive, dark gray, with a tint of green. BRITISH SPONGIADZ. 115 Halbitat—Tenby, J. S. Bowerbank; Fowey, Cornwall, . Mr..C. W. Peach; Jersey, Rev. A. M. Norman. Examined.—In the living state. I have seen but three good specimens of this sponge ; the first I dredged in about seven fathoms, in the sound between Gilter Point and St. Margaret’s Island, Tenby ; the second I received from Mr. Peach, who obtained it at Fowey. They resemble each other very closely, but in the Tenby specimen the primary branches spring from a com- mon base, closely adhering to a stone, while in Mr. Peach’s specimen they originate at a very slight elevation above the base. The subdivisions follow each other at very short distances, and the terminations are frequently trichotomous. Neither of the specimens attained the height of two inches. The colour, when dry, of the Fowey specimen, is nearly that of a dark mahogany; that from ‘Tenby is of a some- what grayish hue; when fresh from the sea it was of a dark gray colour, with a slight tinge of green. ‘The sur- face of the sponge, in the dried state, is abundantly and strongly hispid, and is so rugged and cavernous as to render it very difficult to distinguish the oscula, but they appear to be few in number and irregularly dispersed. ‘This sponge, at first sight, in the dried condition, might be readily mistaken for a stunted variety of D. ramosa, but in the living state the difference in colour and general aspect would readily distinguish them. The skeleton spicula of the two species also closely resemble each other in size, but the spinulate character of the bases of those of D. pu- milus establishes the specific character with a much greater degree of certainty; a few of them are so slightly inflated at the base as to appear nearly purely acuate, but by far the greater number are distinctly more or less spinulate. On the contrary, the skeleton spicula of D. ramosa, what- ever may be its variations in size or form, very rarely pre- sent any indications of inflation of the bases of those organs. The tension and internal defensive spicula of the two spe- cies closely resemble each other, but in the latter of the two forms those of D. pumilus are much smaller than those 116 A MONOGRAPH OF THE of D. ramosa. Tn a small specimen of this species which I received from the Rev. A. M. Norman, who obtained it at Jersey, the tension spicula were exceedingly numerous, and were frequently grouped together in considerable numbers, in the form of large, irregular, flat fasciculi. The specimen was dredged off Jersey. It was attached toa dead shell of Venus verrucosa. It did not exceed an inch in height, but in other respects it closely resembled the specimen from Fowey. 10. Dicrrocyiinprus stuposus, Bowerbank. SPONGIA STUPOSA, var. DAMICORNIS, Montagu. — Rieipa, Montagu. HaLIcHONDRIA CERVICORNIS, Johnston. _ RIGIDA, Johnston. Sponge. Arborescent, pedicelled; branches slender, round, or compressed, dividing dichotomously and _trichoto- mously ; covered with long, scattered spicula projecting at right angles to the axis. Oscula and pores incon- spicuous. Dermal membrane abundantly spiculous ; spicula attenuato-sphero-stellate, radii acute, numerous. Skeleton: spicula of the axis cylindrical, rather short, and stout; radial spicula attenuato-acuate, large and long. Tension spicula acuate and acerate, long and slender, very numerous, frequently fasciculated. Colour.—Light to dark brown, when dried. Habitat. — Torbay, Mrs. Griffiths; Orkneys, Mr. M‘Andrew. Eaamined.—In the dried state. The specimen presented to me by Mrs. Griffiths,. of Torquay, labelled Hal. stuposa, is exceedingly like the figure represented by Montagu, ‘ Wern. Mem.,’ vol. ii, pl. iv, p. 79, in every respect. It differs essentially in its structure from the type specimen of Halichondria cervicornis of Dr. Johnston, figured: in pl. v, fig. 1, p. 96, of his ‘ Hist. Brit. BRITISH SPONGIADE. 117 ‘sponges,’ or, indeed, from any of the specimens described by that author, and appears to be Montagu’s Spongia stuposa, var. damicornis. There is good reason to believe that the specimens figured by Montagu in ‘ Wernerian Memoirs,’ vol. ii, pl. ili, are only stunted varieties of his Spongia hispida, as very similar specimens of that sponge have been found at Hastings, and are in my possession ; and there is also one in Montagu’s collection of sponges in the possession of Dr. Grant, labelled Spongia hispida, which is quite as stunted as the upper of the two figures in pl. ui, vol. i, of the ‘Wern. Mem.,’ while that which Montagu figures in pl. iv, and described as a variety, to ‘be called damicornis,” is the better representative of Spongia stuposa. Ihave therefore thought it advisable so to designate this distinct and well-marked species Dictyo- cylindrus stuposus, and especially as the only other British species, D. ramosus, to which the name stwposus could with any propriety be applied, is undoubtedly Spongia ramosa of Gerard and other authors. Among the sponges in the collection of Colonel Montagu in the possession of Professor Grant, of University College, there is the smaller of the type specimens figured in pl. xi, fig. 2, vol. ii, ‘Wernerian Memoirs,’ but the larger one, represented by fig. 1, is not there. On carefully examining the one represented by fig. 2 I found it to be a stunted specimen of the same author’s &. stuposa, var. damicornis, represented in pl. iv of the same work, but the surface spicula which present so striking a feature in the latter specimen are nearly all absent in the former, which has evidently been much acted on by the sea before it was found. There is no difference in any of the structural characters between the two specimens, excepting that the minute sphero-stellate spicula of the membranes of S. rigida, Montagu, slightly exceed in size those of S. stuposa in my possession, a difference which is by no means uncommon in two specimens of undoubtedly the same species, and which frequently occurs in Zethea lyncurium. I am strongly inclined to believe that the larger of the two type specimens of Sp. riyida figured and described by Montagu is the one 118 A MONOGRAPH OF THE to which he refers as being of an orange colour when fresh, and that it also was a dwarf specimen of his S. stuposa ; if so, 8. rigida of Montagu and Halichondria rigida of Johnston’s ‘British Sponges’ are no longer species, but syno- nyms only. ; The specimen of D. s¢uposus which I received from Mr. M‘Andrew is in better condition than any one of the species that I have yet seen. The thickness of the sarcodous substance surrounding the skeleton is equal to about one third of the diameter of the latter, and in this fleshy coat comparatively very few spicula are disposed in a longitu. dinal direction. Very large attenuato-acuate spicula, as compared with the largest of the spicula of the skeleton, are projected from the cylindrical axis through the sur- rounding fleshy mass at irregular distances. In this spe- cimen the sphero-stellate spicula are in their normal position, immediately beneath the dermal membrane; they are exceedingly numerous, and are seldom more than twice their own diameter apart from each other, but there appears to be but a single layer of them, and it very rarely occurred that a specimen was found deeply imbedded in the fleshy mass, and I could not find any in the sarcode within the axis of the skeleton. The tension spicula are very abundant. They are princi- pally disposed around the axis in numerousirregular, flat fasci- culi, lying usually in the direction of the axis of the sponge, a few of them only occurring at right angles to it; others are dispersed singly and irregularly amid the membranous tissues, and immediately beneath the dermal membrane. The presence of the sphero-stellate spicula in the fleshy substance of H. stuposa, Mont., distinguishes this species readily from all its congeners, and it should be remembered that these spicula are not usually perceptible under ordinary circumstances, but must be rendered so by boiling in nitric acid and mounting in Canada balsam. Montagu’s figure, although roughly executed, is extremely characteristic, and the projection of the surface spicula in the dried specimen to a greater extent than the whole diameter of the axis of the sponge is by no means exaggerated. The axis, when BRITISH SPONGIADA, 119 denuded of these spicula, has the appearance, to the unassisted eye, of woody structure, and it is very rigid and brittle. _ [have not seen fresh specimens of this species, but it is highly probable that when alive the surface spicula would not project to anything like the same extent as represented in the dried condition. 11. DicryocyLinpRrus rucosus, Bowerbank. Sponge. Ramose, pedicelled, branching irregularly, short, thick, and fleshy. Surface rugose, slightly hispid. Oscula simple, large, dispersed, few in number. Pores inconspicuous. Dermal membrane pellucid, aspiculous. Skeleton : axial spicula cylindrical, long, slender, very flexuous; or sub-fusiformi-inequi-acerate, long and slender; rarely acuate. Radial skeleton, fasciculated ; fasciculi compound ; spicula numerous, successive from base to apex, acuate, comparatively short and stout. External defensive spicula, terminal spicula of the radial fasciculi. Colour.—Alive, light gray, with a tinge of yellow. Habitat—Orkney and Shetland, Captain Thomas, Mr. Barlee, Rev. A. M. Norman, and Mr. C. W. Peach. Examined—In the fresh state. ' This sponge is by no means a rare species in the localities named. It rarely exceeds three inches in height, and the principal stem often exceeds half an inch in thickness, It usually begins to divide near its base, generally dichoto- mously, but sometimes trichotomously. ‘lhe branches are frequently somewhat compressed, and they preserve the same diameter for nearly their whole length, terminating obtusely. In the living or fresh state the central axis occupies about one third of the diameter of the sponge. ‘The radial fasciculi have but few spicula at their bases, but they 120 A MONOGRAPH OF THE increase considerably in number as they progress towards the surface, where a few of the terminal ones passing for a short distance through the dermal membrane act as external defensive spicula, rendering the surface, in the fresh state, very slightly hispid, but in the dried condition this character becomes, by contraction, exceedingly prominent. Mr. Barlee dredged this species in sixty to seventy fathoms, about twenty-five miles off Lerwick, near the outer skerries ; and I obtained about sixty or seventy specimens, preserved in salt and water, from the Shetland fishermen, who brought them up with hooks and lines while fishing in sixty or seventy fathoms at the Haaf Banks. In drying, this sponge assumes a deeper yellow colour than it has in the wet state. , Genus—PHAKELLIA, Bowerbank. 1. Phakellia robusta, Bowerbank. 2. — ventilabrum, Bowerbank. 1. PaakeLuia rogusta, Bowerbank. Sponge. Fan-shaped, elevated on a short pedicle ; distal margin attenuated to a sharp edge, surface smooth or very slightly hispid. Oscula simple, dispersed, numerous, and small. Pores inconspicuous. Dermal membrane aspiculous. Skeleton: axial column very slender ; spicula acuate or acerate, large and long, flexuous ; ramuli diffuse ; spicula stout, rather short, acuate, occasionally acerate. Interstitial tension spicula very large and strong, rather numerous, mostly acerate, occasionally acuate, very flexuous, passing at various angles from one radial fasciculus to another. BRITISH SPONGIADZ. 121 Colowr.—Ochreous yellow, when dried. Habitat.—Shetland, Mr. Peach. Examined—In the dried state. This sponge was dredged at Shetland, in 1864, by Mr. J. Gwyn Jeffreys, and preserved for me by my friend Mr. Peach, who accompanied the expedition. It is the only specimen I have seen of the species. It is three inches in height, the same in breadth, and does not exceed four lines in thickness near the base, and gradually becoming thinner towards the distal extremity, where the margin is quite thin and sharp. The dermal membrane is to a great extent destroyed, but where it remains én sifu it appears as if the surface had been smooth and even. In its present dried state it is slightly hispid, by the projection of the spicula of the distal extremities of the secondary ramuli of the skeleton. The dermal membrane has no proper spicula of its own, but in parts it is furnished with large acerate and acuate flexuous tension spicula, of the same description as those which occur soabundantlyin the interstitial membranes, The distal spicula of the secondary ramuli frequently diverge at their apices, approximating to form an external surface to the sponge, and it appears that it is where this divergence does not take place to the necessary extent that the dermal membrane is furnished with the large tension spicula as described above. The axial columns of the primary radial fasciculi of the skeleton are very thin, the great size and strength of the spicula of which they are composed compensating for the want of numbers, and both this portion of the skeleton and the secondary ramuli are formed of spicula of a size greatly exceeding those of the corresponding parts in P. ventila- brum. ‘The spicula of the secondary ramuli, although quite as stout, are not more than about half the length of those of the primary ramuli of the skeleton. The interstitial spaces are very large, and their membranes are abundantly furnished with remarkably large and strong flexuous tension spicula, which frequently have their terminations imbedded in different secondary ramuli; they cross each other at 122 A MONOGRAPH OF THE every imaginable angle, thus forming an irregular but strong connecting network of spicula between the neigh- bouring secondary ramuli. 2. PHAKELLIA VENTILABRUM, Bowerbank. HALICHONDRIA VENTILABRUM, Johnston. Sponge. Cyathiform or ventilabriform, elevated on a short pedicle ; distal margin attenuated to a sharp edge. Sur- faces smooth or somewhat rugose and excavated, minutely hispid. Oscula simple, dispersed, numerous and minute. Pores inconspicuous. Dermal mem- brane aspiculous. Skeleton: spicula of the axes cylindrical, long, slender, and very flexuous ; of the ramuli acuate, slender, rather long, and frequently slightly flexuous. External defensive spicula same as those of the ramuli. Colour.—Pale yellow, with a tint of green, preserved in strong salt and water while alive. Tabitat,-—Haaf Banks, Shetland, Mr. Barlee and Mr. Humphreys ; Loch Fine, Rev. A. M. Norman. Examined.—Fresh and undried, as from the sea. The description of the external characters of this sponge given by Dr. Fleming is very correct applied to dried specimens only, but it may be as well to remark that the difference between the fresh and the dried specimens is so great as to quite alter the specific characters derived from these sources. ‘Thus, specimens which in the former con- dition have the surfaces smooth and imperforate, when dried become highly villous and present quite a reticulated and perforated appearance, in consequence of the contrac- tion of the interstitial tissues, and the real oscula are undis- tinguishable amidst the numerous fractures arising from this cause. In young and well-preserved specimens, which have not been dried, the surface is usually smooth and even, BRITISH SPONGIADA. 123 and the hispid character scarcely perceptible, but in old and well-worn specimens it is frequently rugose, and more or less excavated. The oscula are not readily detected in the fresh sponges ; when apparent they appear as simple circular orifices, rather numerous, minute, and irregularly dispersed on all parts of the sponge. The dermal and interstitial membranes appear entirely destitute of tension spicula ; the former tissue is perforated by the distal terminations of the secondary ramuli, which form innumerable little radiating groups of defensive spicula, projecting through the mem- brane to the extent of about two thirds the length of a spiculum. In the dried condition the primary cylindrical radii of the skeleton have very much the appearance of semi- decomposed ligneous fibre, and the exposure of the secon- dary ramuli by the contraction arising from drying gives the surfaces of the sponge a remarkably flocculent appear- ance, like that of a close thick coat of fine hair or fur, laid in every possible direction by immersion in water. When sections of this sponge in a longitudinal direction are mounted in Canada balsam, and examined by trans- mitted light, with a power of about 150 linear, the primary ramifications of the skeleton are seen to consist of in- numerable long and very flexuous spicula, loosely fascicu- lated together, as in the corresponding parts of a Dictyo- cylindrus, but the spicula in this sponge are very much more contorted in their flexuosity than in any species of Dictyo- cylindrus with which I am acquainted ; and on the external parts of the cylinders these spicula are frequently so dispersed as to appear as if they were portions of threads which had been bound round the central’ fasciculus in an ascending direction, to keep the whole of the included spicula in position. The secondary ramuli of the skeleton are singular in their structure. Their proximal terminations appear to have scarcely any connection with the primary cylinder whence they emanate; they commence with one, two, or three spicula loosely cemented together, but they accumu- late spicula rapidly as they increase in length, dividing 124 A MONOGRAPH OF THE continually, and pursuing an irregular undulating course to the surface, where the distal terminations expand to a very considerable extent. The total length of each ramulus is about equal to that of eight or ten of the spicula of which it is composed. The spicula of which the ramuli are formed, have their apices always directed towards the sur- face of the sponge. I received several of these sponges from my. kind and liberal friend Mr. Barlee, and subsequently through his assistance I obtained between two and three hundred speci- mens from the deep-sea fishermen at the Haaf Banks at Shetland, through their agent Mr. Humphreys, and among these numerous specimens I found every imaginable variety of cup- and fan-like form that can be well conceived. Genus—Microciona, Bowerbank. Section * Skeleton spicula acerate. 1. Microciona fictitia, Bowerbank. Section * * Skeleton spicula acuate. 2. Microciona levis, Bowerbank. — fallax, Bowerbank. — armata, Bowerbank. — spinulenta, Bowerbank. —_— carnosg, Bowerbank. — ambigua, Bowerbank. poe eS Sxction * * * Skeleton spicula spinulate. 8. Microciona atrasanguinea, Bowerbank. 1. Microciona rictit1a, Bowerbank. Sponge. Parasitical on zoophytes or fuci ; surface uneven, BRITISH SPONGIADA. 125 pustulous. Oscula simple, dispersed. Pores incon- spicuous. Dermal membrane spiculous; spicula acerate, long, and slender, dispersed, numerous ; retentive spicula equianchorate, tridentate, minute, short and stout, rather numerous. Skeleton : columns ‘diffuse, long, and very irregular; spicula acerate, rather long and slender. ‘External defensive spicula basally spined, attenuato-acuate or spinulate, long and rather slender, usually curved near the base. Internal defensive spicula entirely spined, attenuato-acuate, short ; spines numerous and strongly produced. In- terstitial membranes spiculous ; tension and retentive spicula same as those of the dermal membrane, both numerous. Colour —Dried, brown with a tint of yellow. Habitat.—Guernsey, Rev. A. M. Norman. Examined.—In the dried state. The specimen in course of description rather exceeds an inch and a quarter in length. It has entirely enveloped, apparently, the stem of a branching horny zoophyte; one portion of it is nearly cylindrical, with a diameter of rather more than two lines ; the other is about the same thickness, but flat, and is rather more than five lines wide. The general aspect of this sponge is so unlike that of other species of Microciona that it is very likely to deceive a hasty observer, and the confusion of its internal structures arising from their true bases being on the cylindrical sur- faces of the zoophyte or fucus whence they spring, instead of on an expanded plane, increases the difficulties of identi- fication ; but a close examination of its structure in detail irresistibly leads to the conclusion that it is truly a Micro- ciona. The depressed pustulous character of the surface in the dried specimen is, with the aid of a lens of an inch focus, very characteristic, but it is probable that it is not apparent in the living sponge. Sometimes the pustules appear to be furnished with a closed osculum, but other oscula are seen 126 A MONOGRAPH OF THE dispersed over the sponge without any connection with the pustular organs. The dermal membrane is furnished abundantly with tension spicula of the same form and size as those of the columns of the skeleton, intermixed with others of the same form, but very slender ; and it has also a considerable number of retentive spicula intermixed with the tension ones. The general aspect of this organ is very much confused, in consequence of the terminations of the skeleton columns frequently curving in the direction of right angles to their long axes, and then spreading irregu- larly over the inner surface of the membrane, so as to pro- duce the appearance of its being furnished with irregular flat fasciculi of tension spicula. ‘This irregular habit of the skeleton columns is, to the best of my belief, peculiar to this species of -Microciona. The skeleton columns are very irregular in their forms and directions ; they are constructed of numerous spicula, disposed longitudinally, and are closely cemented together by keratode. The large external defensive spicula are based on their surfaces, whence they radiate at a great variety of angles, and not infrequently at right angles to their axes. The small internal defensive spicula are not very numerous, they are irregularly dis- persed in all parts of the tissues, and are more frequently recumbent on the interstitial membranes than erect. The retentive spicula are small, but stoutly constructed; the lateral teeth ure widely spread and slightly palmated. The interstitial membranes are numerous and strong, and abun- dantly spiculous, and exhibit on their surface, in a greater or less state of development, every form of spiculum that is found in the sponge, and the retentive spicula are espe- cially numerous in some parts of them. Nearly the whole of the characters exhibited by the interstitial tissues are invisible until the section has been mounted in Canada balsam. BRITISH SPONGIADZ. 127 2. Microciona Lavis, Bowerbank. Sponge. Coating thin; surface even and smooth. Oscula simple, dispersed, minute.. Pores inconspicuous. Dermal membrane spiculous; spicula attenuato-ace- rate, subclavate, long and slender, subfasciculate ; and tricurvo-acerate, stout, central curve abrupt, dispersed, numerous. Skeleton: columns short and_ stout ; spicula numerous, slightly divergent ; attenuato-acuate, large and long. Internal defensive spicula attenuato- acuate, short, entirely spined; spines incipient, dis- persed. Interstitial membranes, tension spicula tricurvo-acerate, stout, central curve abrupt, very numerous. Colour —Nut-brown, when dried. Habitat.—Shetland, Mr. Barlee. Examined.—In the dried state. I am indebted to my late friend Mr. Barlee for my knowledge of this species. I received from him a single specimen, which covered the whole of the imperforate valve of a Terebratula caput-serpentis, and not quite an inch in length. In the dried condition the surface is even, but somewhat rough, but small portions from the parts in best preservation, when immersed in water, presented a smooth and even appearance, and I could not detect any projecting spicula. ; The oscula are not readily determinable, but they appear to be simple and dispersed. The subclavate at- tenuato-acerate tension spicula of the dermal membrane are very long and slender. Sometimes they are loosely fasciculated. Its bundles do not assume any especial direction, but the bases of the spicula of the fasciculi appear to be always coincident. Many other separate spicula of the same form are irregularly dispersed on the inner surface of the dermal membrane. ‘The tricurvo- 128 A MONOGRAPH OF THE acerate spicula are also irregularly distributed. ‘They vary considerably in length and diameter, but they all agree in the abrupt character of the middle curve. The skeleton spicula are large, long, and usually per- fectly smooth ; occasionally, but rarely, an incipient spine may be detected at the base with a power of about 300 linear, but their occurrence is the exception rather than the rule. The internal defensive spicula are short and rather slender. The spines are sometimes strongly developed at the base, but they always present an incipient appearance on the remaining portion of the spiculum. ‘They are seated generally on the basal membrane, but a few are projected from the lower parts of the skeleton columns. In all parts of the interstitial fissures of the sponge the tricurvo-acerate tension spicula are dispersed abundantly. I have designated this species /evis, in reference to the rather unusual smoothness of the skeleton spicula. 3. Microciona FaLLax, Bowerbank. Sponge. Coating, surface rough and uneven. Oscula simple, minute, dispersed. Pores inconspicuous. Dermal membrane pellucid, spiculous ; spicula acuate, long, and slender, dispersed, very abundant. Ske- leton: columns long, slender, and flexuous, occa- sionally branching; spicula acuate, basally spined; spines few and minute. Internal defensive spicula attenuato-acute, entirely spined, variable in size, and occasionally very long; spines very minute. Inter- stitial membranes, tension spicula same as those of the dermal membrane, comparatively few in number. Colour.—Alive, bright crimson; dried, light brown, with a tint of red. Habitat.—Diamond Ground, Hastings. Examined.—lIn the dried state. I received three specimens of this species from Mr. BRITISH SPONGIADA. 129 Henry Ridley, of Hastings, who had them from one of the trawlers. ‘Ihe sponges, each completely covered the upper valve of a Pecten opercularis, and in thickness and general external characters closely resembled each other. The shells were uniformly coated with the sponge, which did not, in any part, exceed the eighth of an inch in thickness. ‘The general anatomical structure, when examined microscopically, so closely resembles that of Microciona carnosa when in a young state, that it might readily be mistaken for that species. The slender, flexuous, and branching characters in the skeleton columns of each are alike, and it is only when we apply a microscopical power to the tissues when mounted in Canada balsam, that the difference in the cha- racters of the spicula of the skeleton and the tension spicula, and the total absence of retentive spicula, which are so abundant in JZ. carnosa, becomes distinctly appa- rent, The basal portions of the skeleton spicula are very sparingly spinous, and the spines are minute; they rarely extend beyond about two diameters of the spiculum above its hemispherical base. The tension spicula are very long and slender, and are frequently flexuous. ‘I'he internal defensive spicula are very numerous and vary much in size ; they are very abundant on the columns of the skeleton, especially towards their basal portions. 4. Microciona AnMatA, Bowerbank. Sponge. Coating thin; surface minutely hispid. Oscula simple, minute. Pores inconspicuous. Dermal mem- brane spiculous, thin, pellucid. ‘Tension spicula sub- clavate attenuato-acuate, long and slender, and angu- loid tricurvato-acerate ; retentive spicula dentato-pal- mate, equi-anchorate and bidentate, equi-anchorate very minute. Skeleton. Columns short and stout ; spicula attenuato-acuate, basally spined, large and long. Internal defensive spicula attenuato-acuate, entirely spined, short and stout; spines of the base numerous, 9 130 A MONOGRAPH OF THE short, and conical, occasionally curved ; spines of the shaft very stout, long, and recurved, especially so towards the apex. Interstitial membranes; spicula same as those of the dermal membrane. Basal mem- brane abundantly furnished with internal defensive spicula. Gemmules spherical, membranous, aspicu- lous. Colour.—Alive, blood-red ;, in the dried state, nut-brown. - Habitat—Belfast Lough, Dr. Dickie; St. Catherine’s Bay, Jersey, Rev. A. M. Norman. . Heamined.—In the dried state. This sponge coats the front of one of the valves of a common mussel-shell for two inches in length and about seven lines in breadth, and its greatest thickness is about two lines. ‘he surface is rough, from the partial destruc- tion of the cuticle and the exposure of a number of sinuous intermarginal canals. In its present condition its texture is rigid, and of a nut-brown colour. In consequence of the destruction of the dermal membrane to so great an extent, I have been unable to determine with certainty the characters of the oscula, but from the size and disposition of the intermarginal canals which conveyed the excurrent streams to them, it is probable they were small’ and dis- persed over the thicker parts of the sponge. The dermal membrane is situated immediately above the terminations of the columns of the skeleton; small portions of its remains, about a line and a half in diameter, were pellucid, and abounded with its characteristic tension and retentive spicula. ‘ihe spicnla of the skeleton are singular, from having the bases furnished profusely with incipient spines or tubercles for about the length of one diameter of the spiculum, beyond which the shaft is completely devoid of spines. ‘The internal defensive spicula have their bases profusely furnished with large conical or recurved spines for about one diameter of the spiculum in length, and the remainder of the shaft. is more sparingly, but still abun- dantly supplied with them, the spines becoming larger and BRITISH SPONGIADA. 131 more recurved from about the middle to the distal ex- tremity of the shaft. These spicula radiate from the columns of the skeleton at angles varying from ten to forty degrees towards the surface of the sponge; and they are. also projected in considerable numbers from the basal membrane of the sponge in the intervals between the bases of the columns of the skeleton at right angles to the basal membrane. The columns of the skeleton are rarely connected with each other by membranes near their bases, but they are abundantly so connected near their apices; and in these membranes we find numerous fasci- cull of the sub-clavated attenuato-acuate tension spicula, and a few of them are also disposed longitudinally in the membranes surrounding the columns of the skeleton. The anguloid tricurvato-acerate spicula are abundant ih all parts of the membranous tissue. These spicula are sifigujar in their character, the middle curves being very short and frequently nearly semicircular, while the terminal ones are long, but very slightly curved, so that the spiculum very nearly approaches the form of the letter V. The retentive spicula are very minute, and require a linear power of about 600 to render them distinctly. I subsequently received two small specimens of this species, dredged off Jersey, in the summer of 1859, by the Rev. A: M.. Norman. The sponges completely coated each of two specimens of Murex corallinus, the largest of which was seven lines in length, and the thickness of the sponge upon it was not more than one third of a line; but it was evidently a mature specimen, as there were a considerable number of gemmules imbedded amidst the tissues. They were spherical and membranous, and entirely destitute of spicula, and full of vesicular molecules. ‘I'hey varied in diameter from j4,th inch to jth inch. My friend describes the sponges, in his letter to me, as, when alive, of “a very pretty blood-red. 132 A MONOGRAPH OF THE 5. Microciona spINuLENtA, Bowerbank. Sponge. Coating thin. Surface rugged and uneven. Oscula simple, minute, numerous. Pores inconspi- cuous. Dermal membrane spiculous ; spicula cylin- drical, sub-clavate, long and slender; dispersed or sub-fasciculate, numerous. Skeleton. Columns short and small; spicula attenuato-acuate, entirely spined ; spines acutely conical, strong, and numerous. In- ternal defensive spicula same as those of the skeleton, few innumber. Tension spicula of interstitial mem- branes same as those of dermal membrane. Retentive spicula bidentate inequi-anchorafe and unipocilate and bipocilate bihamate, dispersed, very minute and few in number. Colour.—Dark brown when dried. Habitat—Squin Ground, Weymouth Bay, J. S. Bower- bank. Examined.—In the dried state. I dredged this species, in 1847, on the Squin Ground, in Weymouth Bay, near the wreck of the Abergavenny. It covers the shells of Pecten opercularis more or less, but always very thinly. It appears to be very common in that locality. I do not recollect the colour in the living state. In the dried condition it is a dark nut-brown. When examined by direct light with a two-inch combina- tion, the surface presented a very rugged and uneven appearance, but in the living state it would probably be much more smooth and even. ‘lhe oscula are small afd numerous ; the largest of them may be seen by the aid of a lens of two inches focus. The dermal membrane is profusely furnished with tension spicula, which are dispersed, or very loosely and irregularly fasciculated. The spicula are slender, long, and usually BRITISH SPONGIAD. 133 more or less clavate at their terminations, and are fre- quently somewhat flexuous. The skeleton columns are short. They are composed of stout attenuato-acuate, entirely and strongly spined spicula well cemented together by keratode. ‘The whole of the spicula do not spring from the basal membrane, a portion of them being successively produced in the course of the development of the skeleton, and the column frequently terminates with four or five of them radiating at various angles. ‘The skeleton spicula vary considerably in size. One of the longest measured vard inch in length, but the greater part of them range from sith to sth inch in length. The spination of the spicula is very abundant, and the spines strongly produced, especially at the base of the spiculum, where they frequently exceed in length half its greatest diameter.- The retentive spicula in this species are very characteristic, but as they are both few in number and yery minute, they are not readily detected, either in situ, after immersion in Canada balsam, or by the dis- solution of a portion of the sponge im nitric acid. They require a microscopical power of about 600 linear to define them distinctly. ‘The average length of the anchorate spi- cula is ;4,th inch, while the ‘unipocilate and bipocilate ones do not exceed ;2;th ch in length. Hach form prevails to about an equal extent, and the greater number of them appear to be seated on the basal membrane. 6. Microcrona carnosa, Bowerbank. Sponge. Coating; surface even, smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane pellucid, spiculous ; spicula fusiformi-acerate, dispersed or loosely fasciculated, numeroys. Skeleton. Columns long, slender, flexuous; abounding in spicula, fre- quently giving off single branches ; spicula sub- attenuato-acuate, entirely spined; stout and long; spines conical. Internal defensive spicula ; attenuato- acuate, entirely spined, shorter than those in the 134 A MONOGRAPH OF THE skeleton, variable in size. Interstitial membranes. Tension spicula fusiformi-acerate, not very numerous ; with a few skeleton and defensive ones intermixed. Retentive spicula bidentate angulated equi-ancho- rate, minute, uniform in size, very numerous. Colour.—Alive, orange-red, Habitat——Sennen Cove, Land’s End, Cornwall, and Diamond Ground, off Hastings, J. S. Bowerbank; Bantry Bay, Ireland, Guernsey and Polperro, Rev. A. M. Norman. Examined.— In both the fresh and dried states. I found this species adhering to the blocks of granite, somewhat protected from the full action of the sea near low water mark, under the point at the south side of Sennen Cove, near the Land’s End, Cornwall, on the 6th of May. The largest specimen was about two inches in diameter and half an inch in thickness, and of a deep orange-red colour. In the living condition the surface was smooth and even, but in the dried state corrugated or slightly mam- millated. No oscula were visible in the living sponge. The dermal membrane is pellucid, and is furnished abundantly with large fusiformi-acerate spicula, which are dispersed or loosely fasciculated. The skeleton columns are long, slender, and often flexuous, and frequently give off short, simple branches, which I have never observed to bifurcate, or to give off secondary branches, and they usually terminate like the primary columns in a cluster of defensive spicula, which radiate in every direction. The skeleton spicula are disposed on the surfaces of the columns and in accordance with the axis; they are longer than the defensive ones, and more inclined to be regularly acuate. The defensive spicula are decidedly attenuato-acuate, they vary considerably in size. ‘hey are very numerous, and are disposed on the column at all angles to its axis. One of these sponges is permeated by some small tubular zoophyte, which it has coated with its own tissues, and from these adopted columns defensive spicula are projected, in a similar manner to those of the columnar skeleton. BRITISH SPONGIADA. ; 135 The interstitial membranes are abundant, apparently strong, and are often sinuous in their course. ‘They are furnished with the same description of fusiformi-acerate tension spicula as those of the dermal membrane, but very much more sparingly, and a few of the skeleton or defensive spicula are occasionally embedded amongst them. ‘The retentive spi- cula are very abundantly dispersed over the surfaces of the interstitial membrane as well as on the inner one of the dermal membrane; they are minute, and very uniform in size. The sarcode is abundant on the interstitial mem- branes, and completely obscures the retentive spicula until a thin section of the sponge is mounted in Canada balsam. The general aspect of this species, both in the living and dried states, so closely resembles that of Hymemacedon caruncula that I fully believed it to be that species until I had examined it microscopically. I subsequently received a specimen of this sponge from the Rev. A. M. Norman. It was collected at Bantry Bay, and coated a group of shells of a vermetus, nearly two inches in length by one in breadth. ‘The surface of the sponge is very much more rugged and uneven than that from Corn- wall, arising probably from immaturity and the peculiarities of its locality. In all its anatomical details it agreed perfectly with the Cornish specimen. Mr. Norman’s specimens were found “on a rock situated about the middle of the entrance of Glengarriffe Bay, extreme low water mark,” In January, 1865, I received a specimen, at Hastings, from the Diamond Ground, oval in form, three and a half inches long, one and a half inches wide, half an inch thick ; when alive it was of a full red flesh colour, and the surface with very slight inequalities, but when dried it was exceed- ingly rugged and mammillated by the projection of the terminations of the columns of the skeleton. This species may be readily mistaken for MZ. fullax, at the first view, but when mounted in Canada balsam, and examined with a power of about 400 linear, the abundance of its retentive spicula, and the differences existing in the structure of its skeleton and tension spicula, render the 136 A MONOGRAPH OF THE discrimination of the two species comparatively easy and satisfactory. 7. Microcrona amBiaua, Bowerbank. Sponge. Coating; surface even, slightly hispid. Oscula simple, dispersed, minute. Pores inconspicuous. Dermal membrane, spiculous ; spicula acerate, long and slender; sub-fasciculated. Skeleton. Columns very short, and indistinctly produced; spicula atte- nuato-acuate, basally spined, large and long, irregular in size. Internal and defensive spicula attenuato- acuate, entirely spined; short and stout. Interstitial membranes; tension spicula cylindrical, entirely spined, frequently sub-attenuated, distorted, and curved considerably ; very numerous. Retentive spicula angulated bidentate equi-anchorate ; and, rarely, pal- mated equi-anchorate. Colour.—Wet condition, light ochreous yellow; dried, light brown. Habvitat.—Shetland. Leamined—FKresh from salt-and-water pickle, and in the dried state. The specimen described above coated the expanded extremity of one of the valves of a large shell of Pinna ingens (P). It covers a space of seven and a half by six and a half inches, and in no part exceeds a line in thickness. On the smooth portions of the shell the surface of the sponge is even, and in the wet condition no oscula could be detected by the aid of a lens of an inch focus; but in the dried state several were apparent in the mature portions of the sponge. In the young and progressing margins of the sponge the extreme edge appears as a thin film of gelatinoid matter, im which a few tension spicula are irregularly dispersed; within this marginal portion the BRITISH SPONGIADZ. 137 tissue becomes thicker, and the tension spicula numerous and more approaching regularity of disposition, but there is no appearance of the columnar skeleton and its peculiar spicula; so that a young and immature specimen might readily be mistaken for a species of a different genus; but in the mature sponge this mistake cannot readily occur. Although the keratose columns of the skeleton are but very slightly produced, their fasciculi of large and characteristic spicula render such an error very improbable. ‘The skeleton columns, generally speaking, are but very indistinctly pro- duced ; the keratose portion frequently forming on the basal membrane a slight elevation only, from amidst which one or more of the large skeleton. spicula sprung ; or it is repre- sented by the cementing keratode that binds them together for a short distance in their progress upward; but the peculiarities of their size, form, and mode of arrangement will always indicate, unmistakeably, the genus to which this species belongs. “The dermal membrane is profusely furnished with its peculiar spicula, which are more or less fasciculated, and these bundles extend more especially from group to group of the skeleton spicula, which they appear to serve, to maintain, and support in their respective positions. One third or half of the distal extremities of the skeleton spicula are frequently projected through the dermal membrane, thus performing the office of external defensive spicula as well as of skeleton ones. The internal defensive spicula nearly all spring from the basal membrane of the sponge. They are generally grouped around the base of the skeleton columns, but they also appear independent and isolated, and occasionally they are based about midway on the side of the skeleton columns. They rarely exceed a fourth of the length of a fully developed skeleton spiculum, and are always entirely spined. The interstitial membranes are abundantly supplied with tension spicula, especially so the basal membrane of the sponge, on which they are so thickly dispersed as to simu- late the appearance of a secondary skeleton ; they are rather shorter than the internal defensive ones, or about a fifth of 138 A MONOGRAPH OF THE the length of an average size of skeleton spiculum, about half a line. The skeleton spicula occasionally, although rarely, attain the length of a line, and this extension of the ordinary length usually obtains when the skeleton column is repre- sented by a single spiculum, which has its base in the basal membrane and its apex projected through the der- mal one. There is a paucity of keratode, and an immaturity in the production of the skeleton columns, which appears to indicate a young condition of the sponge ; this is assuredly the case in the marginal portions, and notwithstanding the large area of its surface I am strongly inclined to believe that no part of it is in a fully developed condition, and that hereafter, in older specimens, the skeleton columns will be found in a much more satisfactory state of de- velopment. 8. Microciona ATRASANGUINEA, Bowerbank. Sponge. Coating thin, surface minutely hispid. Oscula simple, minute, numerous. Pores inconspicuous. Dermal membrane pellucid, thin, spiculous; tension spicula acuate or sub-clavate, long and slender, and a few tricurvato-acerate ; retentive spicula bidentate, equi-anchorate, few in number. Skeleton columns short and stout ; spicula of the body of the column fusiformi-attenuato-sub-spinulate, short and rather stout ; of the terminations long and, large, curved outwardly, projected through the dermal membrane for half or two thirds their length, as external de- fences. Internal defensive spicula sub-spinulo-acuate, entirely spined, few in number. Interstitial mem- branes rare; spicula same as those of dermal mew- brane, few in number. Colour.— Alive, dark blood-red ; dried, brown or dirty green. ; BRITISH SPONGIADA. 139 Habitat. — St. Katherine’s Cave, ‘lenby. Rocks off Hastings at low water; Guliot Caves, Sark ; Sennen Cove, Land’s End, Cornwall, J. S. Bowerbank. Examined.—In the living state. ‘his sponge occurs abundantly in the small cave about the middle of the north side of St. Katherine’s Island, ‘Tenby ; accessible without a boat only at very low tide. Its appearance is that of a small patch, from one to two inches in diameter, of dark clot of blood adhering closely to the surface of the rock, and it can be obtained only by cutting away’ the piece of stone to which it adheres. It rarely exceeds about half a line in thickness. Its extreme thinness readily distinguishes it from the deep red coloured sponge, Chalina seriata, which occurs abundantly along with it in that cave, and which is so thick as to be easily removed from the rock with a knife. In the living condition I could not detect the oscula, but in the dried state, by the aid of a two inch lens, they appear to be numerous, and dispersed equally over the surface of the sponge. I could not find the pores. ‘The columns of keratode rarely exceed in height the length of one of the large skeleton spicula, and are frequently not more than half or a third of that length ; they never appear to anastomose with each other, but are united at their bases by a uniform thin stratum of keratode or con- densed membranous basal tissue, in which is imbedded, without order, numerous slender sub-clavato-acuate spicula, with a few tricurvato-acerate ones, and from the bases of the columns we find occasionally a single entirely spined sub-clavato-attenuato-acuate defensive spiculum projected. ‘The dermal membrane also abounds with the same descrip- tion of spicula that we observe in the basal stratum. It is situated immediately above the apices of the keratose columns, and in the intervals between them it is supported and strengthened by the numerous long slender tension spicula which cross each other in various directions; the large terminal spicula passing through it powerfully protects it from injuries from without. 140 A MONOGRAPH OF THE The spicula of the skeleton are unlike those of any other sponge with which I am acquainted. They are curved considerably, and constricted at about once their own diameter from the base, so as to become sub-spinulate ; beyond this constriction they dilate rather suddenly, and are fusiform for about one third their own length, and thence to the apex they are regularly attenuated ; some- times the sub-spinulation is scarcely perceptible, or entirely absent, but the fusiform character appears to be constant. The bases of the skeleton spicula are not immersed in the keratose column, but are firmly cemented to its external surface. They are projected from all parts of it, at angles varying from 10 or 12 to 45 degrees, and the terminal ones form a radiating defensive group, from three to five or six in number, the convex side of the spiculum being always outward. The extreme height from the base of the kera- tose column to the apices of the terminal spicula in two cases measured, was 3th and 3th inch. The anchorate spicula are few in number, and are irre- gularly dispersed on the dermal membrane; they are very minute, and a few of them appeared to be palmato-anchorate. The growth and development of the pedestals is very interesting. The terminal groups of the large defensive spicula are first developed on the basal membrane in a sessile condition, and the increment of the keratode is from beneath them; they are thus gradually elevated from the basal membrane, the lateral spicula being successively pro- duced in accordance with the necessities of their positions. I have obtained this species abundantly from the small reefs of rock exposed at low water opposite the town of Hastings, through the medium of Mr. Henry Ridley, where he states it frequently covers the surface of the sandstone in patches ten or twelve inches in diameter, and I have one speci- men in my collection about seven inches long by four in breadth. Although thus spreading so widely, it does not appear to increase in thickness. However carefully dried, after a time it loses its red colour, and assumes a brown or a dirty green hue. A hasty observer may readily mistake this species for BRITISH SPONGIADA. 141 M. armata; the general aspect of the two when mounted as sections in Canada balsam are very similar, but the greater length and strength of the terminal spicula of the skeleton columns, the powerfully recurvedly spinous internal defen- sive spicula, and the anguloid tricurvate-acerate tension: spicula so abundant on the interstitial membranes of JZ. armata, on a closer examination readily séparate the two species. Genus—Hymerarpnia, Bowerbank. Snction * * Skeleton spicula, acuate. 1. Hymeraphia vermiculata, Bowerbank. — clavata, Bowerbank. Section * * * Skeleton spicula, spinulate. 3. Hymeraphia verticillata, Bowerbank. 4, — stellifera, Bowerbank. ]. HyMERAPHIA VERMICULATA, Bowerbank. Sponge. Coating ; surface uneven and cavernous ; strongly hispid. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane spiculous ; spicula acuate, long, and exceedingly slender, variable in size ; fasciculated ? Skeleton and external defensive spicula acuate, large and long. Spicula of the basal membrane inequi- acerate,. vermiculoid, rather large and stout, exceed- ingly variable in tortuosity. Colour.—Dried, light buff yellow. Halbilat.—Shetland, in deep water, Mr. Barlee, Mr. C. W. Peach, and Rev. W. Gregor. Ezxamined.—In the dried state. 142 A MONOGRAPH OF THE IT am indebted to my friend Mr. Barlee for this interest- ing species. I received four specimens, three of which were coating small pebbles. None of them exceeded four lines in diameter, and the thickness not more than that of a sheet of writing paper. ‘The colour is a light buff yellow, and with a lens of two inches focus the long spicula may be seen projecting from the surface of the sponge, like minute bristles. By the aid of a Lieberkuhn and a power of 100 linear, the surface appears very uneven, full of abrupt depressions and elevations, and a few minute simple oscula were apparent. When a portion of the sponge was removed from the stone and mounted in Canada balsam, the dermal mem- brane appeared to be very delicate, and to be lined with a thin coat of sarcode, but I could not either by this mode. of mounting, or by any other means, detect the spicula of that membrane 7 stu. On treating a piece of the sponge with boiling nitric acid, in a small dished cell, I obtained them in considerable numbers, and the greater portion of them were collected in regular fasciculi; and from this mode of arrangement, and the peculiarities of their struc- ture, there is no doubt in my own mind that they were liberated by the action of the acid from the dermal mem- brane. They are so slender that they require a linear power of 500 or 600 to define their structure and propor- tions accurately. ‘lhe skeleton and external defensive spicula appear enormously large in proportion to the thick- ness of the sponge and its remaining tissues. ‘lhe whole of them have the base firmly cemented to the basal mem- brane, whence they. are projected through the mass of sarcode, the dermal membrane, and far beyond its surface, and at about right angles to it. The basal membrane of this sponge presents a novel and very singular appearance. It is abundantly furnished with inequi-acerate vermiculoid spicula lying on the surface of the membrane, and presenting an appearance very like a congregation of the vibriones of sour paste. No two of them are alike in their contortions, length, or thickness, and in their disposition they pass under and over each BRITISH SPONGIADA. 143 other in every possible manner, so as completely to form a loose felting of siliceous spicula. The basal ends of the large skeleton ones pass through this stratum of spicula, and in several instances I observed that the points of the vermi- culoid ones coiled closely round their bases so as materially to assist them in maintaining their position on the basal membrane. _ - The vermiculoid spicula do not appear to be equally abundant in every specimen of the species, as in sponges subsequently examined they were comparatively few in number, and in one case they were dispersed and uncon- nected with each other, and this did not appear to arise from an immature condition of the sponge, as in other respects it appeared to be fully developed. . [have subsequently received specimens on old shells and pebbles, from the Rev. Walter Gregor, dredged in the Moray Frith, and others from Mr. Peach. None of these specimens exceeded three fourths of an inch in diameter. 2. HymerapuHia cLavata, Bowerbank. Sponge. Coating thin; surface even, strongly hispid. , Oscula simple, dispersed. Pores inconspicuous. Der- mal membrane spiculous; spicula attenuato-acuate, long and slender, fasciculated, fasciculi frequently arranged in radiating groups. Skeleton and external defensive spicula attenuato-acuate, long and stout, rarely sub-clavate, variable in size and length. Internal defensive spicula attenuato-clavate, eutirely spined. Tension spicula attenuato-acuate, long, and very slender, fasciculated. Basal membrane pellucid, smooth, and even. Sarcode abundant. Colour.—Dried, light amber. Habitat—Shetland, Mr. Barlee; Moray Frith, Rev. Walter Gregor. Examined.—lIn the dried state. 144 A MONOGRAPH OF THE I have to thank my friend, Mr. Barlee, for this new species. He took two specimens at Shetland during his deep sea dredging at that locality, in 1858. One coats a portion of the outer surface of a valve of a dead shell of Astarte Scotica, covering a space of about eight lines in diameter. It is exceedingly thin, and, in the dried state, can only be distinguished from the dark periostracum of the shell by the grains of extraneous matter which are abundant on its surface, and by the reflection of the light from the long spicula which are projected from it. The height of the sponge from the basal membrane on which the bases of the skeleton spicula are fixed, to the apex of the largest of them, does not exceed about a line. T could not get a section of the sponge at nght angles to its base, but if we may judge by the length of the internal defensive spicula, the height from the base to the dermal surface would not exceed 1-150th of an inch.—The second specimen covered the surface of a small pebble for the space of three fourths of an inch in length by half an inch in breadth, and the sponge presented the appearance of a thin, brown incrustation. ‘I'he minute oscula, irregularly dis- persed on its surface, were visible by the aid of a lens of two inches focus. When a portion of the sponge was im- mersed in Canada balsam, the dermal membrane was seen to be abundantly furnished with tension spicula, sometimes dispersed singly, but most frequently collected in fasciculi, which were often congregated in radiating groups. The inner margin of an osculum on this piece of the sponge was well supplied with internal defensive spicula. The large spicula of the sponge serve the purpose of both skeleton and external defensive spicula. ‘They are projected at nearly right angles from the basal membrane, and extend far beyond the dermal surface ; among them, and imbedded in the sarcode, I found one very stout, short, cylindrical spiculum, but this I believe to be only an abnormal form of the usual skeleton ones, which, with very rare exceptions, are regularly acuate. The internal defensive spicula vary considerably in size; I measured one of the longest and one of the shortest of BRITISH SPONGIADA. 145 them, and they were 4th of an inch and ;th of an inch in length. The whole of them are distinctly clavate at the base. The spines are short, conical, acutely terminated, and very numerous. The tension spicula of the interstitial tissues are exceed- ingly slender; the greater portion of them are collected into fasciculi, each containing a considerable number of spicula, the bases and apices in each bundle being always coincident. The fasciculi occur singly, and are irregularly dispersed on the surface of the basal membrane. A solitary spiculum may be observed occasionally, but this appears to - be rather the exception than the rule. Ina young specimen of this species sent to me by the Rev. Walter Gregor, late of Macduff, from the Moray Frith, the skeleton spicula were nearly all clavate or sub-spinulate, but this variation in their form was evidently due to incomplete development, the rest of the spicula also exhibiting evidence of immaturity. The colour, when alive, was light yellow. The specimen was dredged from forty-two fathoms, six miles off shore. 3. HyMERAPHIA VERTICELLATA, Bowerbank. Sponge. Sessile, coating ; surface uneven, with numerous conical projections. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane pellucid, abundantly spiculous ; spicula fusiformi-cylindrical, verticellately spined, very variable in size, dispersed. Skeleton : spicula attenuato-clavate, large and long, distal termi- nations obtuse, few in number; surrounded by nu- merous long and slender inflato-acerate spicula, with incisurate terminations. Interstitial membranes. Ten- sion spicula very numerous, the same as those of the dermal membrane. Basal membrane abundantly spiculous; same as those of the dermal membrane ; and long, slender, inflato-acerate spicula, with incisu- rate terminations, dispersed or loosely fasciculated. Ovaria membranous, aspiculous. 10 146 A MUNOGKAPH OF THE Colour.—Cream white. Locality—Western coast of Ireland; 100 fathoms. Captain Hoskins. Haamined.—Preserved in spirit. This interesting species was brought up from a depth of 100 fathoms, by the sounding line, by the officers of H. M. ship Porcupine, and was sent to me for examina- tion by my friend, Professor Wm. King, of Queen’s College, Galway. It is in three pieces, neither of which exceeds half an inch in length and about two lines in thickness. The surface has a very peculiar appearance, being studded at irregular intervals with conical projections, which are produced by the distal terminations of the skeleton fasciculi pressing against the inner surface of the dermal membrane, and thus projecting it above the general surface of the sponge. The skeleton of this species differs from other British Hymeraphias in having the primary skeleton spicula each surrounded by a fasciculus of secondary skeleton spi- cula, serving to strengthen and extend the lines of the skeleton. These spicula are closely clustered around the primary ones; they are large and long, and attenuate gradually from the inflation at the middle to each termi- nation, which presents a singular bifid appearance. The spicula of the dermal and interstitial membranes are also very remarkable, as they are the only verticellately spined spicula that are yet known to occur in a British sponge; the other two instances of the existence of verticellately spined spicula being in West Indian species, and in both these cases they are internal defensive organs, while in this sponge they are decidedly tension spicula. In the young state these spicula occasionally appear to be moniliform, and without spination, but this variation in form appears to arise from incomplete development. 4. HYMERAPHIA STELLIFERA, Bowerbank. Sponge. Coating, exceedingly thin. Surface even, strongly BRITISH SPONGIAD. 147 hispid. Oscula and pores inconspicuous. Dermal membrane inconspicuous. Skeleton and external defensive spicula, attentuato-clavate, long and slender, variable in length. Internal defensive spicula clavato- attenuato-cylindrical ; apex stellately spinous. Basal membrane pellucid, smooth, and even. Sarcode thick and abundant. Colour.—Dried, light amber yellow to orange yellow. Habitat.—Shetland, Mr. Barlee; Moray Frith, Rev. Walter Gregor ; Frith of Clyde, Rev. A. M. Norman. Exzamined—TIn the dried state. I am indebted to my friend Mr. Barlee for two speci- mens of this interesting species. They were taken by him in the course of his deep-sea dredging at Shetland, in the year 1858. They occupy the insides of two valves of dead shells. In one of them, Docinia lincta, there is a thin patch of the sponge seven lines in length, and five in width. In the other shell, Zapis aurita, there is a specimen very similar in appearance to the first one, of six lines in dia- meter. The appearance of the sponge in both cases is like that of a thinly spread patch of gum or glue-water, dried on the surface of the shell; but with the aid of a lens of an inch focus, and by a little management of the light, the long projecting spicula of the sponge may be seen standing out from its surface in abundance. ‘The sponge is ex- tremely thin, the height from the basal membrane to the surface measured but jth inch; and from the basal membrane, whence the long spicula proceed, to the apex of the longest spiculum in the field of the microscope, 3th inch. I could not detect either oscula, pores, or a dermal membrane. When immersed in water the sarcode ex- panded to rather above the line of the largest of the internal defensive spicula, and the surface presented the usual slightly undulating gelatinoid appearance of that substance, but I could not detect either interstitial membrane or cavities. The whole of the Jarge spicula of the sponge serve the 148 A MONOGRAPH OF THE double purpose of skeleton and defensive spicula ; their bases are attached to the basal membrane of the sponge, and their direction is always at nearly right angles to it. They vary in length from th inch to zth inch, and their structure is very remarkable; the clavate base is largely and strongly produced, while the shaft attenuates rapidly, and terminates in an extremely slender apex in the longest of them, while the shorter ones are much stouter in their proportions. This great inequality in length renders them very much more effective in their character of external de- fensive organs. Intermixed with the large attenuato-clavate spicula there are a few extremely slender acuate ones, but as their basement and their direction is precisely the same as the larger ones, I believe them to be only a very early stage of their development. The internal defensive spicula, like the skeleton ones, are planted in the basal membrane, and their general direction is at about right angles to it. They vary in height from goth inch to 2,th inch, and their form is much like that of a Florence oil-flask with an elongated neck, and an orna- mental stellate stopper, the stout conical radii or spines passing off in every direction, but emanating only from the apex of the spiculum. The spines terminate acutely, and their height is about twice that of their basal diameter. These spicula are not readily to be detected when the sponge is immersed in water, and it is only after immersion in Canada balsam that they become distinctly visible. T subsequently received from the Rev. A. M. Norman a small branch of Mullipora calcarea? about four lines in length, and one and a half in diameter, covered with this sponge. The colour was much deeper and more inclined to red than that of Mr. Barlee’s specimens. It was obtained by dredging off the Isle of Cumbrae, in the Frith of Clyde. It has also been obtained from the Moray Frith, by the Rev. Walter Gregor, late of Macduff. The specimens sent to me by that gentleman were in very fine condition, and the colour was a bright orange-yellow. There were three on the fragment of a large bivalve shell, but no one exceeded an inch in diameter. BRITISH SPONGIADA. 149 Genus—Hymepesmia, Bowerbank. Section * * Skeleton spicula acuate. 1. Hymedesmia radiata, Bowerbank. Section * * * Skeleton spicula spinulate. 2. Hymedesmia stellata, Bowerbank. Section * * * * Skeleton spicula cylindrical. 3. Hymedesmia Zetlandica, Bowerbank. 1. Hymepesmia RADIATA, Bowerbank. Sponge. Coating, very thin, surface even, smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane aspiculous, pellucid. Skeleton composed of numerous widely-radiating groups of long and slender attenuato-acerate spicula; groups irregularly dispersed ; and also exceedingly large and long acuate or sub-clavated acuate spicula, irregularly dispersed amidst the skeleton tissues. Internal defensive spicula clavated attenuato-acuate, incipiently entirely spined, stout and variable in length, very numerous. Colour.—Dried, light greenish-gray. Habitat.—Shetland, Mr. C. W. Peach. Ezamined.—In the dried state. I am indebted to my friend Mr. Peach for this specimen, the first of the species I have seen. It coats very thinly a space on the surface of a fragment of a granite boulder, of about an average of two inches in diameter. It was dredged at Shetland, by Mr. J. G. Jeffreys, in 1864, and was pre- served for me by Mr. Peach, who accompanied the expe- 150 A MONOGRAPH OF THE dition. ‘The surface in the dried state has a few of the longest of the internal defensive spicula with their apices projecting through the dermal membrane, but this, I appre- hend, is due to the contraction of the sponge in drying. The oscula are minute, and are only visible by the aid of an inch lens. The dermal membrane, strictly speaking, is aspiculous, as there are no tension or retentive spicula appropriated either to it or to the interstitial membranes ; but the large and widely-spreading groups of skeleton spicula are occasionally based on its inner surface, and thence radiate into the body of the sponge. But by far the greater number of these radiating groups are based on the basal or the interstitial membranes ; the spicula of the skeleton require a linear power of about 400 to render their form distinct. Their bases are irregularly crowded together, while their shafts are projected outward at every imaginable variety of angle. The supplementary large acuate or sub-clavated acuate spicula are a singular appen- dage to the skeleton ; they are of extreme length, and more than twice the largest diameter of the spicula of the radial groups, and are disposed in lines parallel to the basal membrane ; they are usually disposed singly, but occasionally two occur together, or very closely so. The internal defensive spicula are very numerous, and appear all to spring from the basal membrane, their diameter is nearly the same at the base, but they vary greatly in their length and also in the degree of their spinations; in some the spines are quite in an incipient state, while in others they are well and distinctly produced. 2. HYMEDESMIA STELLATA, Bowerbank. Sponge. Coating very thin; surface even, hispid. Oscula simple, dispersed, minute. Pores inconspicuous. Dermal and basal membranes abundantly spiculous; spicula cylindro-stellate, very minute. Skeleton: spicula ovo-spinulate, very large and long, variable in size, closely fasciculated, bases and apices concurrent. BRITISH SPONGIADA. 151 External defensive spicula attenuato-acuate or sub- spinulate, occasionally abnormo-spinulate. Interstitial spicula dispersed or fasciculated; bases and apices concurrent in the fasciculi; attenuato-spinulate, very slender. Colour.—Dried, light fawn. f Habitat.— Guernsey, Rev. A. M. Norman. Examined.—In the dried state. I have seen but one specimen of this species. It coats a space equal to a square of the size of about half an inch, in a straggling, irregular manner, on the inside of the half of an old bivalve shell. The surface is strongly hispid, by the projection through the dermal membrane of the external defensive spicula. The dermal membrane is so crowded with the cylindro-stellate spicula, as to greatly impede the view of the interior of the sponge; these spicula are very minute, and require a microscopic power of 600 or 700 hnear to define them accurately. The ovo-spinulate spicula of the fasciculi of the skeleton are very large and long, and their oviform bases are large and well produced. The fasciculi are very compactly formed, and the bases and apices always occupy the same relative positions. The fasciculi do not assume any particular direction, but are irregularly dispersed amid the tissues. The basal mem- brane appears to be as crowded with stellate spicula as the dermal one, but the sponge is so very thin that it is diffi- cult to distinguish the one from the other; whether viewed through the back or the front of the sponge, the skeleton fasciculi are always beneath the stellate membrane, so that no doubt can exist as to its presence. The external defen- sive spicula springs from the basal membrane, and pass for a great portion of their length through the dermal one, radiating thence in every direction; they are not so regular in their form as those of the skeleton, and are regularly attenuated from their bases to their apices. The interstitial spicula appear to be dispersed to about the same extent ; they are fasciculated, and are much smaller and more slender than the external defensive ones. 152 A MONOGRAPH OF THE 8. Hymeprsmia Zerianpica, Bowerbank. Sponge. Coating very thin; surface smooth and even. Oscula simple, dispersed. Pores inconspicuous. Der- mal membrane pellucid, aspiculous. Skeleton : spicula sub-biclavated, cylindrical, numerously fasciculated, rather large, of nearly uniform size and proportions. Internal defensive spicula attenuato-acuate, entirely and strongly spined ; large and stout, rather numerous ; spines conical, acute, often recurvate. Retentive spicula bidentate and tridentate equi-anchorate, rather stout and numerous, dispersed ; and simple bihamate, large, but very slender, fasciculated, fasciculi numerous, dispersed. Colour —Dried, buff yellow. Habitat.—Deep sea, Shetland, Mr. Barlee. Examined.—In the dried state. T am indebted to my indefatigable friend Mr. Barlee for this sponge. He obtained it in the course of his deep-sea dredging at Shetland, in 1858. There are two small patches of it on the front margin of a valve of Docinia exolita, one on the outer and the other on the inner surface of the shell; neither of them exceed a quarter of an inch in diameter. I have also three other small specimens of it of similar dimensions, on the two sides of a flat pebble about three fourths of an inch in diameter, from the same locality. One of them is in juxtaposition with a specimen of Hymeraphia vermiculata, trom which it may be readily distinguished by a lens of an inch focus, by its smooth surface, and by the total absence of large external defensive spicula. I could not detect the oscula without the aid of a microscopic power of about 100 linear, and by direct light. They were few in number, and very small. The spicula in the fasciculi of the skeleton are very numerous. The bundles are dispersed irregularly in all parts of the sponge, BRITISH SPONGIADA. 153 between the basal membrane and the dermal one, some- imes crossing each other, but frequently entirely isolated. Their length very little exceeds that of a single spiculum. The internal defensive spicula are large and stout in their proportions. They vary in length from th inch to J,th inch. In some of the dried specimens of the sponge the points of the larger ones project beyond the surface, giving it when viewed by direct light, with a power of 100 linear, a slightly hispid appearance ; but as this evidently arises from the contraction of the sponge in drying, it is not probable that it would be apparent in the living state. They are dispersed on the surface of the basal membrane, at about equal distances from each other. Their spination is very abundant to within a short distance of the apex, which is smooth and acute, and at the base of the spiculum they are abundant and very strongly produced. The retentive spicula are most abundant on the inner surface of the basal membrane, but a few comparatively, are dispersed in the interstitial tissues among the fasciculi of the skeleton. The bidentate and tridentate equi-anchorate spicula are stout and strong in their proportions, and the dentz are more than usually widely spread. They are dispersed equally on the surface of the basal membrane. The simple bihamate spicula are about twice the length of the anchorate ones, but their shafts are of extreme tenuity, a portion of them are in groups, as if the bundles had been partially broken up and dispersed, and occasionally isolated spicula occur, but their usual mode of disposition is in compact fasciculi, each consisting of a considerable number of spicula, the hami being all coincident. This is the first instance I have met with in which spicula of this form have been collected in fasciculi. The thickness of this species in the dried condition does not exceed ,,th inch; in the living state it may probably be Ath inch in thickness, but although of such slight dimensions, the fully developed condition of all its organs indicates an adult state of the specimen. 154 A MONOGRAPH OF THE Hymenracipon, Bowerbank. Section * Skeleton spicula, acerate. 1. Hymeniacidon Thomasii, Bowerbank. COMO op 10. coccinea, Bowerbank. Brettit, Bowerbank. Jragilis, Bowerbank. reticulatus, Bowerbank. fallaciosus, Bowerbank. albescens, Bowerbank. lactea, Bowerbank.., perarmatus, Bowerbank. membrana, Bowerbank. Szction * * Skeleton spicula, acuate. Sub-section A. Skeleton spicula, smooth. 11. Hymeniacidon caruncula, Bowerbank. 12. sanguinea, Bowerbank. mammeata, Bowerbank. consimilis, Bowerbank. variantia, Bowerbank. macilenta, Bowerbank. Jallar, Bowerbank. viridans, Bowerbank. perlevis, Bowerbank. aurea, Bowerbank. armatura, Bowerbank. pachyderma, Bowerbank. crustula, Bowerbank. lingua, Bowerbank. foreum, Bowerbank. virguitosa, Bowerbank. Sub-section B, Skeleton spicula, spinous. 27. Hymeniacidon plumosa, Bowerbank. 28. Jecusculum, Bowerbank. BRITISH SPONGIADA. 155 Section * * * Skeleton spicula, spinulate. Sub-section A, Skeleton spicula, smooth. 29. Hymeniacidon suberca, Bowerbank. 30. — carnosa, Bowerbank. 31. — jicus, Bowerbank. 32. — sulphurea, Bowerbank. 33. —_ sub-clavata, Bowerbank. 34. — clavigera, Bowerbank. 35. — celata, Bowerbank. 36. — gelatinosa, Bowerbank. Sub-section B, Skeleton spicula, spinous. 37. Hymeniacidon paupertas, Bowerbank. Section * * * * Skeleton spicula, cylindrical. 38. Hymeniacidon Dujardinii, Bowerbank. Section * * * * * Skeleton spicula, angulated. 39. Hymeniacidon Buckland, Bowerbank. 1. Hymentacipon Tuomas, Bowerbank. Sponge. Sessile massive, surface rugose. Oscula slightly elevated, few, dispersed. Pores conspicuous, not very abundant. Dermal membrane pellucid, thin, abun- dantly spiculous. Spicula: of the skeleton, acerate, stout, few ; of the interstitial membranes, acerate, slen- der, abundant. Colour.—Dried, buff yellow. " Habitat.—Black Rocks, Leith, Capt. F. W. L. Thomas, N. Examined.—In the dried state. 156 A MONOGRAPH OF THE The form of this sponge is nearly circular, the diameter being about two and a half inches. It is so much de- pressed that it does not exceed half an inch in thickness. There are two smooth spaces on the under side, about three eighths of an inch in diameter, which have apparently been pomts of adherence to a smooth surface. The re- mainder of the inferior portion is much like that of the superior one, excepting that there are no osculaapparent,these organs being confined to the upper surface and margin of the sponge ; they are dispersed about an inch apart, and the largest rather exceeds two lines in diameter. The pores are apparent to the unassisted eye; they are com- paratively not very numerous. The spicula of the skeleton are stout and slightly curved, and are comparatively by no means abundant ; while those of the membranous structures are exceedingly numerous; the latter are slender and slightly curved. The dermal membrane is abundantly fur- nished with the slender spicula, intermixed with a small number of the larger ones. The interstitial membranes are crowded with the slender spicula, irregularly felted together, as it were, amid which the skeleton spicula are dispersed at intervals, singly or in small groups, comparatively con- siderable spacesgin the membranes being without them. At the first view dried specimens of this species may be readily mistaken for H. caruncula, the rugose surface being very similar to that of the latter species. . I am indebted for this sponge and many other valuable specimes to the liberality and kindness of my friend Capt. F. W. L. Thomas, R.N., who has done so much to advance our knowledge of marine natural history during his services as commander of the Hydrographical Survey in the Orkneys, Shetland, and the Frith of Forth, and in commemoration of which I have much pleasure in attaching his name to this new and interesting species. 2.HyMENIACIDON coccinEA, Bowerbank. Sponge. Amorphous sessile. Surface uneven, rugged. BRITISH SPONGIADZ. 157 Oscula minute, dispersed, numerous. Pores incon- spicuous. Dermal membrane pellucid, abundantly spiculous, dispersed, same as those of the skeleton. Skeleton : spicula subfusiformi-acerate, large and rather long, and the same form short and slender. Gem- mules membranous. Colour.—Alive, scarlet, dried, light gray. Locality.—Salcombe Bay, Devonshire, Mr. Alder. Examined.—In the dried state. I received two specimens of this sponge from my friend, Mr. Joshua Alder, of Newcastle-on-Tyne. In the box con- taining them there was also a small specimen of Hymenia- cidon caruncula, from the same locality, and from the external appearances of the two species it would have been impossible to have distinguished the one species from the other ; and it would appear that the same difficulty exists in the living state. On referring to Mr. Alder regarding the colour when alive, he wrote as follows: “I have no re- collection about the sponges I got in Salcombe Bay, and the colour was the only memorandum I preserved. As I had put them together, I must have supposed them to be the same species, and I have therefore no doubt that they would be similarly coloured.” This similarity in colour would be very likely to mislead a casual observer, but the difference in form at once distinguishes the species. In the dried state H. coccinea and H. Thomasii might be mistaken for each other if external characters alone were referred to, but a comparison of the spicula of the two species readily distinguishes them, those of the latter species being nearly twice the size of the spicula in the former one. Immediately beneath the dermal membrane there was a considerable number of membranous gemmules, variable in size, and each containing the usual granular vesicles. 158 A MONOGRAPH OF THE HYMENIACIDON BRETTII, Bowerbank. Sponge. Encrusting, surface smooth, minutely reticulated. Oscula simple, small, dispersed. Pores inconspicuous, numerous. Dermal membrane rather stout, pellucid, abundantly spiculous. Spicula of the skeleton fusi- formi-acerate, stout ; tension spicula of the interstitial membranes acerate, slender. Colour.— Alive, externally cream, internally yellow. Habitat.—Tenby, Mrs. Brett and J. S. Bowerbank ; Menai Straits, Mr. Alder. Ezamined.—In the dried state. I received this species, among others, from Mrs. Brett, of Tenby, by whom it was found on St. Katherine’s Rock, between high and low water marks. The sponge was nearly covered by a specimen of Isodictya rosea. It is nine lines in length, six in breadth, and does not exceed three in thickness. The surface is undulating and smooth, and is minutely reticulated ; when viewed through an inch lens it has much the same appearance as that of Halichon- dria panicea, but the reticulations are finer than in that species. The oscula are very small, not exceeding one third, or one fourth, of a line in diameter, and although so minute they are not numerous. The pores are abundant and equally distributed over the whole of the surface, and are in a great measure the cause of its reticulated appear- ance. The dermal membrane is rather stout, but pellucid. It is abundantly spiculous, and the spicula are collected into loose, and often continuous fasciculi, which have a tendency to cross each other at nearly right angles; the prevailing spicula are the slender acerate ones, but there is a considerable intermixture of the stout fusiformi-acerate ones of the skeleton. I have named it in honour of its discoverer, Mrs. Brett, or BRITISH SPONGIADA. 159 of Tenby, an ardent and successful cultivator of marine natural history. . HYMENIACIDON FRAGILIS, Bowerbank. Sponge. Branched and inosculating, sessile ; surface un- even, smooth. Oscula simple, dispersed. Pores in- conspicuous. Dermal membrane pellucid, spiculous ; spicula fusiformi-acerate, arranged in an’ irregular multispicular network. Skeleton spicula fusiformi- acerate, stout, irregular in size. Colour.—Alive, various shades of green and flesh colour. Habitat.—Mouth of the Dart, Devonshire, Bowerbank. Ezxamined.—In the fresh state. This sponge is exceedingly common about a mile within the mouth of the Dart, where an abundance of it was cast up by the tide. It is extremely fragile at all times, and when dry very light and friable ; the general texture of the sponge is exceedingly cavernous and irregular. Although the surface is uneven and rugose, it is in no respect hispid, as the dermal membrane follows every sinuation of the exterior. The colour of many of the specimens when fresh was more or less green, and a portion of them flesh- oo The dried specimens generally assume a pallid ue. . Hymenracipon RrEtIcuLatus, Bowerbank. Sponge. Sessile, coating. Surface even, smooth. Oscula congregated in marginated areas, or simple and mar- ginated. Pores inconspicuous. Dermal membrane translucent, spiculo-reticulate, rete irregular, strong, and multispiculate. Skeleton: spicula acerate, stout, and acuate, slender. 160 A MONOGRAPH OF THE Colour.—Dried, light fawn or cream-colour. Habitat.—Strorna, Shetland, Mr. C. W. Peach. Examined.—In the dried state. At the first glance at this sponge, with a two inch lens, the student might readily mistake it for a dried coating specimen of Halichondria panicea, the reticulated surface of each so closely resembling the other; but the pecu- liarities of the oscula areas will quickly remove such an erroneous impression. ‘These organs are remarkable in their characters. In some of the areas five or six oscula of various sizes are congregated, while others contain but a single osculum. The margins of the areas are slightly elevated, and are thin at the edges, and fora short distance surrounding them the reticulations of the dermal membrane are obsolete, and in their places we find the spicula ar- ranged in nearly parallel hnes, converging towards the margin of the area, renderig the tissues close and dense in their structure. The same arrangement prevails around the margins of the single oscula. The reticulations of the dermal membrane are very irregular in size, and the spicula of the network far too numerous to be counted. In other respects, the tissues of this sponge are extremely simple, the spicula of all parts being of the same form, but somewhat variable in size. The sponge covers a surface of about one and a half square inches, and does not exceed about two lines in thickness. It is seated on a portion of a flat boulder, and was dredged by Mr. J. Gwyn Jeffreys, at Shetland, in 1864, and preserved for me by my friend Mr. Peach, who accompanied the expedition. 6. HYMENIACIDON FALLACIosus, Bowerbank. Sponge. Sessile, coating fuci or zoophytes. Surface smooth, minutely reticulated. Oscula simple, dis- persed. Pores inconspicuous, Dermal membrane translucent, spiculo-reticulate ; rete irregular, multi- BRITISH SPONGIADA. 161 spiculate and strong ; spicula acerate, large. Skeleton. Abundantly spiculous ; spicula large and long. Colour.—Dried, lurid pale green. Habitat.—Coast of Northumberland, Rev. A. M. Nor- man. Fwvamined—In the dried state. I received a single specimen of this sponge from the Rev. A. M. Norman. It entirely enveloped a cluster of Tubularia two and a half inches long, and was, at its broadest part, nearly an inch inwidth. A cursory observer would be very liable to mistake it for a specimen of /Jali- chondria panicea in its dried state, the reticulated surfaces of each being very similar; but the difference in their ana- tomical structure readily distinguishes them. The same reticulated surface also exists in dried specimens of Z. reticulatus, but the dissimilarity in colour, and the disper- sion of the oscula, instead of being congregated in mar- ginated areas serves to distinguish them. The anatomical structure of each is also very similar, and they are not readily separated by description alone, but when the structures of the two species are microscopically com- pared, the difference in the size of the spicula, and the shorter and stronger character of the whole of the struc- tures of H. fallaciosus compared with those of H. reticu- latus is strikingly apparent; an adult spiculum of the former being to a full grown one of the latter as five to three, with a corresponding increase of diameter. 7. HYMENIACIDON ALBESCENS, Bowerbank. HaticHonpRia ALBESCENS, Johnston. Sponge. Massive, sessile; eliminating one, or rarely more, irregularly cylindrical virgultose branch, or branches from its apex; branches occasionally dividing into two. Surface smooth. Oscula simply ea 162 A MONOGRAPH OF THE few in number. Pores inconspicuous. Dermal mem- brane pellucid, aspiculous. Skeleton. Spicula fusi- formi-acerate, large and Jong. Colour.—Alive ; lemon-yellow; dried state, white. Habitat.—Berwick Bay, Dr. Johnston; Roundham Head, Torbay, Mr. Gosse ; Guliot Caves, Sark, J. S. Bowerbank. Examined.—In the living state. I am indebted to my friend, Mr. Gosse, for my first knowledge of this species, as although described by Dr. Johnston, in his ‘ History of British Sponges,’ I could not find it among the sponges deposited by him in the British Museum, as the types of the species described in that work. Mr. Gosse states that he found the specimens he sent to me “on the under surfaces of boulders and crom- lechs of soft red sandstone, at Roundham Head, Torbay,” and he also describes the colour when alive as “a pale buff or drab,” and that they were abundant. A few weeks after receiving them from Mr. Gosse, I found the same species in the sides of the rocks of the celebrated Guliot Caves, in the island of Sark, in considerable quantity. The sponge in its living condition is of a lemon yellow colour, but it loses this tint in drying, and becomes of a silvery white. Dr. Johnston’s description of its colour would, therefore, be correct, supposing his specimens to have been found on fuci cast up by the sea, and the sponge in a dead condition. In the living condition, the surface is quite smooth, but in the dried state it is often slightly hispid from the contraction of the sponge in drying, and the consequent protrusion of some of the spicula near the surface, through the dermal membrane. ‘The specimens which I found in the Guliot Caves were most frequently parasitical on Zoophites or on small Balani, and in this habit they also agree with those found by Dr. Johnston. From all these circumstances, I am strongly inclined to believe that the species found by Mr. Gosse and by me, and that designated by Dr. Johnston Halichondria albescens are the same. BRITISH SPONGIADA. 163 The tallest specimen did not exceed two and a half inches in length, and was about a line in diameter, until near the distal end, when it expanded to about a line and a half. This specimen was from Torquay. ‘The stoutest specimen was from the Guliot Caves in Sark ; 'it was two inches long, was largest about the middle, and the greatest diameter was three lines. The base consists of a small irregular sessile mass, from the top of which a single virgultose branch springs, gene- rally very much more attenuated at the lower end than at its middle or near its apex, where it frequently expands to one and a half or twice its previous diameter; sometimes but not very frequently assuming a pear-shaped distal extremity, but more frequently gradually attenuating from the expanded portion to its apex. Occasionally, the branch divides into two, but this is not of very frequent occur- rence. In young, and apparently immature specimens, the basal mass 1s often not present, the sponge consisting of a single irregularly cylindrical virgultose branch, and in this con- dition it frequently attains two inches in height. The structure of this species is very simple, no other form of spicula existing in it than those of the skeleton, but they are very abundant and variable in size. I could not detect the oscula in the living specimens, but in the dried condition they were very apparent, but few in num- ber. In the latter condition, the pores also were visible when viewed by direct light with a power of 100 linear. The specimens were abundant for about six feet from low water mark at spring tides, in the sides of the north end of the furthest of the two large caves from the approach by land, and which can be only reached by land at low spring tides. SHymEnractpon LactEea, Bowerbank. Sponge. Coating, surface smooth and even. Oscula simple, dispersed, minute. Pores inconspicuous, 164° A MONOGRAPH OF THE Dermal membrane pellucid, abundantly spiculous ; spicula acerate, long, and slender, dispersed. Skele- ton. Spicula acerate, long, and slender, larger and stouter than those of the dermal membrane. Colour.—Dried, milk white. Habitat.—Moray Firth, Rev. Walter Gregor. Examined.—In the dried state. This remarkable sponge existed in several small patches, on a fragment of a dead shell of a large Pecten, about two inches in length by one in breadth. There were six or seven small patches, none of which exceeded three lines in breadth, or about six or eight in length, and the thickness did not in any one exceed that of thin writing paper. The dermal membrane is crowded with spicula of the same form as those of the skeleton, but somewhat less in length and diameter. It is difficult to trace the interstitial membranes, as the sponge is so thin that it is, in truth, nearly all dermal membrane, and in many places in the pieces examined, there appeared to be nothing in the shape of interstitial tissues between the dermal and basal mem- branes. 9. HYMENIACIDON PERARMATUS, Bowerbank. Sponge. Coating, thin; surface smooth and even. Oscula numerous, dispersed, slightly elevated. Pores incon- spicuous. Dermal membrane pellucid, abundantly spiculous ; spicula dispersed, acerate, long, and large ;. profusely furnished with large equi-anchorate bi- and tri-dentate retentive spicula. Skeleton. Spicula acerate, long, and large, very abundant. Interstitial membranes abundantly furnished with large bi- and tri-dentate, equi-anchorate, retentive spicula: In- ternal defensive spicula attenuato-clavate entirely spined, large, very variable in length and size. Colour.—Dried, light buff yellow. BRITISH SPONGIADA. 165 Halitat.—Forty miles east Outer Skerries, Shetland, Rev. A. M. Norman. Examined.—In the dried state. I am indebted to my indefatigable friend the Rev. A. M. Norman for my knowledge of this species; he obtained it by dredging. The specimen is nearly two inches in length and breadth, and about a line and a half in thickness. The oscula are nearly uniform in size, none exceeding about a line and a half in diameter, and they are elevated above the surface about one third or half aline. The spicula of the dermal membrane are the same as those of the skeleton ; and among them the bi- and tridentate equi-anchorate retentive spicula, are abundantly dispersed, and compara- tively they are very stout and large; no internal defensive attenuato-clavate spicula appear among them, ‘I'he skeleton spicula are exceedingly abundant, and are very closely matted together, and occasionally they are sub-fasciculate. The internal defensive spicula frequently exceed the skeleton ones in length. The extremely long ones appear all of them to spring from the basal membrane of the sponge, while the shorter varieties are situated on the interstitial membranes. The spination of these spicula is exceedingly abundant especially at their club-shaped bases. These spicula very closely resemble the corresponding organs in Hymeniacidon clavigera, but there is no difficulty in dis- criminating the species, as their skeleton spicula are dis- tinctly different in form. 10. HYMENIACIDON MEMBRANA, Bowerbank. Sponge. Coating, thin ; surface smooth and even. Oscula dispersed, simple or slightly elevated ; few in number, and rather large. Pores inconspicuous. Dermal membrane abundantly spiculous. Spicula same as those of the skeleton. Skeleton. Spicula acerate, small, but not long in proportion; numerous ; very rarely acuate. 166 A MONOGRAPH OF THE Colour.—In the dried state, cream white. Habitat—Surface of stones between tide-marks, Lerwick, Rev. A. M. Norman. Feamined.—tIn the dried state. I received seven speeimens of this sponge, spread out and dried on paper, from the Rev. A. M. Norman, who found it on stones at Lerwick. ‘The largest measured about two and a half inches long, by nearly two inches wide, and in its dried state it was scarcely thicker than the piece of stout paper to which it was attached. In general appearance the specimen very closely resembled large patches of stout animal membrane, such as those of the thinnest portion of the diaphragm of a sheep. There is a great paucity of structural characters in this species. No other forms of spicula appear to exist in it than those of the skeleton, and the difference in size and proportions of the spicula of the skeleton and those of the dermal and interstitial membranes is scarcely to be recog- nised. It is fortunate that its external characters are strikingly different from those of the species to which it is most nearly allied in structure. 11.Hymentactpon caruncuna, Bowerbank. Sponge. Coating, thick; surface uneven, but smooth. Oscula, simple, small, dispersed, few. Pores incon- spicuous, minute. Dermal membrane pellucid, thin, abundantly spiculous ; spicula acuate, slender, irregu- larly dispersed, very numerous. Skeleton. Spicula acuate, rather stout. Interstitial membranes, tension spicula acuate, slender. Colour.—Alive, from light to deep orange. Habitat—St. Katherine’s Cave, Tenby; Guliot Caves, Sark; Hastings; Mill Bay, near Land’s End, Cornwall, J. §. Bowerbank; Bantry Bay, Ireland, Rev. A. M. BRITISH SPONGIADS, 167 Norman; Salcombe Bay, Devon, and Menai Straits, Mr. Joshua Alder ; Weymouth Bay, Mr. William Thompson, Examined..—In the living state. This species is one of the best types of the structural peculiarities of the genus to which it belongs. It is abun- dant on the rocks between high and low water mark in St. Katherine’s Cave, at Tenby, and on other parts of the neigh- bouring rocks. It occurs in irregular patches, sometimes five or six inches in diameter, and from half to one inch in thickness, varying in colour from a light yellow orange toa deep red orange, and sometimes having a slight tint of green. In its live condition it is firm and flesh-like, both to the sight and the touch, and this appearance attends it also in the dried state. The oscula are few in number, and rarely exceed a line in diameter. The pores are barely visible in a dried specimen through a two-inch lens. The dermal membrane is abundantly supplied with spicula, similar in form to those of the skeleton, but much more slender ; they are closely, but regularly, matted together. The tension spicula are not numerous ; they are of the same form as those of the skeleton, but slender and often flexuous, and some of them are of extreme tenuity. I never detected gemmules in either the Tenby or the Sark specimens ; but in one from Bantry Bay, three and a half inches in length by about one and a half broad, and half an inch in thickness, sent to me for examination by the: Rev. Mr. Norman, I found them scattered rather sparingly ' through the tissues. They were spherical, membranous, and aspiculous, and filled with minute vesicles. The largest I observed measured ,3,th of an inch in diameter, and a smaller one sth of an inch. The colour was that of dark red amber. The specimen sent to me by Mr. William Thompson, of Weymouth, was five inches in length, three inches in width, and about three fourths of an inch in thickness, having the surface covered with small rugged mammeform projections. In April, 1854, I found several specimens of this sponge on the base of the rocks at low- water mark spring tides opposite the archwav dividing St. 168 A MONOGRAPH OF THE Leonard’s from Hastings. In many cases it was completely covered by Halichondria panicea, and was to be seen only when the latter was removed from the rock by a knife. Although thus covered, it was apparently in a healthy con- dition, and was covered with mammeeform projections of about the eighth of an inch in height. The colour was deep orange red. ‘I'he specimens I found at Mill Bay, Cornwall, were smooth and even at the surface in the live state, but assumed a slightly corrugated state when dried. T have in some specimens observed that the dermal and in- terstitial membranes have been minutely granulated, but this does not appear to be a constant character ; when pre- sent, it requires a power of about 500 linear to render the granules distinctly visible. 2. HYMENIACIDON SANGUINEA, Bowerbank. SPONGIA SANGUINEA, Grant. HALICHONDRIA SANGUINEA, Fleming. _ _ Johnston. Sponge. Encrusting ; surface smooth and undulating, or rugged, with ridges or elevations. Oscula simple, numerous, small. Pores inconspicuous. Dermal membrane abundantly spiculous; spicula acuate, long and slender, irregularly dispersed. Skeleton. Spicula acuate, stout and long, often slightly flexuous. Colour,—Alive, deep blood red. Habitat—Dublin Bay, Lambay Island, William Thomp- son, Esq. ; Berwick Bay, Dr. Johnston ; Staffa, Iona, Isle of Skye, Dr. Grant; Island of Bofin, Connemara, Rev. Robert Hudson; Roundstone Bay, Ireland, and Island of Arran, Ireland, J. S. Bowerbank. 7 Eeamined.—In the dried state. In the Johnstonian collection of British sponges at the British Museum there are five specimens, labelled Hali- chondria sanguinea, distinguished as 27a, 276, 27¢, 27d. BRITISH SPONGIADA. 169 27a has two pieces on the card so numbered, one larger than the other, and each differing from the other in specific characters. ‘The smaller specimen, labelled 27a and 27d, are the same species, and appear identical with Mymeni- acidon caruncula of this work ; 276 and 27c are the same species, having spicula of the same form as those of H. caruncula, but very much longer; 27a, the largest speci- men, has spicula of an acerate form, differing entirely from the other four specimens. ‘Thus, in the five specimens we recognise three species under the single designation of Halichondria sanguinea. The two specimens distinguished as 276 and 27¢ appear to answer best to the description given by Dr. Johnston of his Halichondria sanguinea, and I therefore propose to confine the specific name Sanguinea to them. ‘They differ considerably from each other in size and the characters of the surface, so much so that Dr. Johnston has labelled 274 as an abnormal form, but this discrepancy, when we consider the difference in size and development of the two specimens, is of very little value in this tribe of sponges. 27c is thirteen inches long, by seven lines wide, and about the eighth of an inch in thickness, and is stated to have been found in Berwick Bay, and we may therefore presume that it agreed in colour with the de- scription given of H. sanguinea in his work, as well as in having the acuate spicula long. The specimen labelled 276, Halichondria sanguinea ab- normal, is very much larger than any of the other specimens with which it is associated. It is nearly three inches long, by two inches broad, of an irregularly oval form, and its greatest thickness rather exceeds half an inch. The surface “Is very uneven and rugged, full of conical projections and short ridges, some of which are nearly half an inch in height. ‘The oscula are numerous and comparatively large ; they are situated both on the sides and the apices of the ridges or cones, which cover the surface of the sponge. An Aymeniacidon caruncula the acuate spicula are con- siderably shorter than in the sponge to which I propose to confine the term Sanguinea, but beside this difference in character, there are others which assist us in our discrimi- 170 A MONOGRAPH OF THE nation of the species. Thus Dr. Johnston states his H. sanguinea to be of “a deep blood-red colour,” and Dr. Grant also states that “it has always the same deep red colour,” while I have never found Hymeniacidon caruncula of a blood-red, and never approaching that colour nearer than that of a full orange tint, which in drying always changes to a rich cream yellow, sometimes with a shade of reen. : On measuring the length of a full-sized spiculum of the sponge marked 27c, it proved to be 4rd of an inch long, while a full-sized spiculum of H. caruncula, from Tenby, measured ;1;th of an inch in length. Since writing the above I have received five specimens of this species from my friend the Rev. Robert Hudson, who found them “ under a rock at the Island of Bofin, midway between Achil Head and Slyne Head, Connemara. One of the specimens measured six inches long, four broad, and about eight lines thick in the dried state, and one specimen exceeded an inch in thickness, and in the dried condition all of them were of a deep blood-red, and my friend de- scribes them when alive as of “a deep scarlet colour.” I found this species at near low-water mark at the Isles of Arran, Galway, of a deep blood-red colour, with some- times a superficial tint of green. 13. HYMENIACIDON MAMMEATA, Bowerbank. Sponge. Sessile, coating; surface furnished abundantly with large and prominent mamme ; minutely hispid. Oscula and pores inconspicuous. Dermis stout; dermal membrane pellucid, abundantly spiculous; spicula acuate, slender, dispersed. Skeleton. Strong and cavernous, abundantly spiculous; spicula fusiformi- acuate, large, and long, and the same form small and slender. External defensive spicula fusiformi-acuate, short and small, very numerous. Colour.— Dried, nut brown. BRITISH SPONGIADA. 171 Hatitat,—Three miles off Dunstanborough, Rev, A. M, Norman. Examined.—In the dried state. At the first sight, this sponge might readily be mistaken for a variety of Polymastia mammillaris. It is about two inches in diameter, and does not exceed half an inch in thickness, and its surface is abundantly furnished with the mammeeform organs, some of which exceed half an inch in length, two lines in diameter, and about one line at the distal extremity. Others are broader, shorter, and more conical, no two appearing to be precisely alike in form and proportions. Their anatomical structure is also entirely different from the similar shaped organs on Polymastia, their interior being filled with the same de- - scription of skeleton tissue as that forming the body of the sponge, and this mass of interstitial structure is tra- versed. by several excurrent canals, which run nearly parallel to each other from the base of each of the mamme to the apex. The interior structure of the sponge is also re- markable, the abundance of spicula in the membranes of the skeleton, their consequent thickness, and the large size of the intermarginal cavities, causes the specimen in the dried condition to simulate very closely the appearance of the skeleton of a Desmacidon; but a microscopical ex- amination of its structure speedily relieves us of any doubts regarding its true character. This species in the dried state may be readily mistaken for H. consimilis by a hasty examination, but for the difference in its colour, and in the proportions of its spicula as compared with those of that species which are in length only as four to seven in the sponge under consideration. The posses- sion of external defensive spicula also, which do not exist In H. consimilis, serve still further to distinguish them. No oscula could be detected on the mass of the sponge, but from the structures of the mammz their absence might be expected, the numerous and large longitudinal canals on those organs sufficiently indicating their office and the position of the oscula, although not visible under 172 A- MONOGRAPH OF THE the present circumstances. The dermal tension and de- fensive spicula are exceedingly abundant in all parts of the external surface of the sponge, and so also are the spicula of the skeleton on the membranes on which they are dis- posed. 14.HyYMENIACIDON consIMILIS, Bowerbank. Sponge. Sessile, coating. Surface rugose, but not hispid, furnished abundantly with large and prominent mamme. Oscula simple, dispersed. Pores incon- spicuous. Dermis stout; dermal membrane pellucid, abundantly spiculous, spicula rather short and stout, same as those of the skeleton, depressed, very nume- rous. Skeleton. Abundantly spiculous ; spicula sub- fusiformi-acuate, short, and stout, numerous. Colour.—Alive, bright orange, sometimes with a tint of green. When dried, externally, greenish gray ; internally, deep red. Habitat—Belgrave Bay, Guernsey ; and Herm, between tide marks, Rev. A. M. Norman. Exvamined.—tIn the dried state. T received six specimens of this species from the Rev. Mr. Norman. The largest was nearly two and a quarter inches in diameter, and rather short of an inch in thick- ness; the smallest an inch and half in length, by three fourths of an inch in breadth, and rather exceeding half an inch in thickness. The upper surface of each of them was so completely crowded with mammeeform bodies as to entirely obscure the dermal surface of the sponge; in the larger specimens, they were inclined at various angles towards the surface of the sponges, but in the three smaller specimens they were at nearly right angles to the surface. Their normal form appears to be conical, but they are subject to great variations in shape, sometimes being acutely conical about three or four times the height of the BRITISH SPONGIADS. 173 diameter of the base, at others, terminating very abruptly and obtusely. In some of the oldest specimens, two, three, or more of the mamme unite at their bases, formin a stout short column for about half their height, but ter- minating in separate short cones. In the dried state, their surfaces are very much corrugated by collapse of the dermis inward. Their usual height is five or six lines, with a basal diameter of about two lines. The structure of the exteriors of these organs is the same as that of the body of the sponge, each one having two or three large excur- rent canals extending the whole of their length; I could not detect any terminal oscula, but in several instances I found open oscula on their sides, rather smaller than those dispersed on the body of the sponge. There are two species with which this sponge may pos- sibly be confounded. The greenish gray dermis, and deep red interstitial tissues of H. consimilis closely resemble the corresponding tissues of Hf. sanguinea, and the spicula of the skeleton of the former are of the same form as those of the latter species; but they are rather shorter, and con- siderably stouter than those of ZH. sanguinea. The dermal membranes of both species are abundantly furnished with irregularly dispersed spicula, but they are much more numerous in A. consimilis. 'These comparatively slight differences would scarcely have led us to have considered them as distinct species, if it were not that the striking differences in form are such as to at once claim our atten. tion. I have scen many species of H. sanguinea, and have never observed the slightest indication of the production of the irregular mammeeform organs which are so abundant on all the six specimens of H. consimilis. These strictly external characters, therefore, become of greater value in this case than is usually attributed to them; and in addition to the structural differences, slight as they are, after a careful ex- amination, they appear to fully warrant the separation of the two species. ‘The reverse of the case which I have Just described exists in the comparison of H. consimilis and H. mammeata. Here we have the massive sessile forms and mammeated surface of each species closely resembling 174 A MONOGRAPH OF THE the other. The general anatomical characters of the inter- stitial structures also harmonise in a remarkable manner ; and the spicula of the skeletons are of the same form; but there is one important difference which is decisive in the separation of the species, and that is the great differ- ence existing in their proportions, the spicula of A. mam- meata, being nearly twice the length of those of H. con- similis ; the former being to the latter as seven to four ; an amount of difference that is never found to exist in the organs of any two specimens of the same species, how- ever they may vary in size, age, or mode of development. The hispidation of the surface of H. mammeata also serves as an essential differential character. My. Norman has in- formed me that he found this sponge living “on the upper surface of rocks between tide marks near low-water at Belgrave Bay, Guernsey, and at Herm, and that it lives in places exposed to the full light and rays of the sun.” 15. HyYMENIACIDON VARIANTIA, Bowerbank. Sponge. Massive; surface rugged. Oscula simple, dis- persed, numerous. Pores inconspicuous. Dermal membrane pellucid, spiculous ; tension spicula acu- ate, minute, fasciculated, retentive spicula, bihamate, simple, and contort, large, and small. Skeleton. Spicula, acuate, elongate, often flexuous, occasionally short and flecto- or inflato-acuate, rarely acerate or cylindrical. Interstitial membranes ; tension spicula acuate, stout, few in numbers and acuate, very minute and slender, numerous, and most abundantly with fasciculi of minute acerate, and large and small bihamate spicula, Sarcode abundant. Colour.—Alive and dried, light gray. Habitat.—St. Katherine’s Rock, Tenby, Mrs. Brett. Exvamined.—Dried, ‘The type specimen in its present form is eight lines in BRITISH SPONGIAD. 175 length by six in breadth, and the same in height, but it is evidently a portion only of the original mass. Mrs. Brett, to whom I am indebted for my knowledge of this species, obtained it between the tide marks on the northern side of St. Katherine’s Rock, at Tenby, and the colour, I am in- formed, was the same when alive as when dried, light gray, approaching closely to white. The variation in the size, and the modifications in the form of the spicula of the skeleton is remarkable. The normal form is evidently acuate, elongate, and not flexu- ous; the short and stout varieties of the normal form are often flecto-attenuato-acuate, and the longer and more attenuated varieties of the normal form are usually more or less flexuous. Acerate or cylindrical spicula are of rare occurrence, and are often inflated near the middle of the spiculum. The skeleton spicula vary from 3th to 3th of an inch in length. The same tendency to great variation in size here prevails among the bihamate spicula, but of these there appears to be two distinct groups, one ranging im length from ,,th to th of an inch, and the other from sath to sath inch. The latter are infinitely more numerous than the former ones, but both are inter- mixed on the surface of the membranes without the slightest appearance of arrangement, while the minute acerate spi- cula of the same tissues are usually collected in fasciculi, irregularly disposed on the surface of the membranes. These spicula do not exceed th part of an inch in length, and are exceedingly slender. The slender flexuous acuate spicula abound on the surface of the interstitial membranes, and they are also intermingled with those of the skeleton. The flecto-acuate spicula are considerable in number, and somewhat uniform in size, but I could not ascertain that they were peculiar to any one portion of. the sponge. The Inflato-acuate are rather rare, the inflation is tolerably uni- form in size but not in position, sometimes being in the middle of the shaft, and at others near its base. In the dried condition, the texture of this sponge is very open and cavernous. 176 A MONOGRAPH OF THE 16.HYMENIACIDON MACILENTA, Bowerbank. © Sponge. Sessile, coating thinly Zoophytes, &c. Surface smooth, but uneven and rugged. Oscula simple, dis- persed. Pores inconspicuous. Dermal membrane abundantly spiculous; tension spicula sub-clavate acuate, long and very slender, numerous, dispersed ; and a few tricurvato-acerate, long and slender ; ter- minal curves nearly obsolete ; retentive spicula, inequi- bidentate and dentato-palmate anchorate, the two in about equal quantities, small and few in number; and dentato-palmate anchorate very minute, few in number ; also contort-bihamate, large and very numerous. Skeleton. Spicula sub-clavate acuate, rather short and stout. Interstitial membranes: spicula same as those of the dermal membrane. Colour.—Alive, scarlet; dried, dark brown. Habitat—Island of Herm, Rev. A. M. Norman. Examined.—lIn the dried state. I received two specimens of this sponge from the Rev. A. M. Norman, each consisting of several fragments ; the largest piece slightly exceeded an inch in length, and was about three lines in width. In the dried state the aspect of the sponge is like that of a thin slice of flesh, roughly dried, with the blood coating it; in the living condition Mr. Norman states that it was of a bright scarlet colour. The basal enlargement of the skeleton spicula is usually very slight, and in many of them it is scarcely perceptible, but it is as prevalent in the young skeleton spicula and in the skeleton tension ones as it is in the fully-developed skeleton spicula. The acuate tension spicula are exceedingly slender and long in proportion to their diameter ; they fre- quently attain the length of half that of an adult skeleton one; the tri-curvate ones also attain about the same length, the central curve is well produced, but the terminal ones are BRITISH SPONGIADA. 177 sometimes scarcely to be perceived. ‘The largest of the an- chorate spicula are by no means numerous; both forms are about equal in size; the small ones are very minute, and do not exceed about one third the length of the larger de- scriptions of those organs, and they also are very few in number, and are by no means easily detected am situ, even when mounted in Canada balsam. Among the retentive spicula, the contort bihamate ones are by far the most numerous, and form one of the most striking characters of the species; they are about three times the length of the largest of the anchorate ones, and are stout in proportion, and they appear to abound in all parts of the membranous tissues. 17 Hymuntactpon FALLAX, Bowerbank. Sponge. Massive, sessile; surface smooth, but uneven. Oscula simple, dispersed. Pores inconspicuous, not numerous. Dermal membrane thin, transparent, with a dense, irregular stratum of spicula, attached to and immediately beneath it. Skeleton. Spicula, acuate, sub-fusiform, and rarely sub-spinulate. Interstitial membranes : spicula of the same form as those of the skeleton, but slender and flexuous. Sarcode abundant. Colour.—Dried, light ash colour. Locality —Torbay, Mrs. Griffiths. Examined—When dry. The form of the only specimen I have seen of this species is that of an irregularly compressed fig. It is an inch and a half in height, by one inch in breadth, and does not ex- ceed half an inch in thickness. I have designated it Jallax from the close resemblance that exists between its spicula and those of Hymeniacidon Alderi, but the sub-spinulate character is wanting in the latter species. If it should prove hereafter that the external form and general character of H. fallax is tolerably constant, those 1 178 A MONOGRAPH OF THE characters will generally serve to distinguish the one from the other, and among the structural characters the marked difference that exists between the dermal membranes and their associated spicula, and the absence of granulation in the dermal and other membranes of H. fallax, will aid es- sentially in the separation of the two species. I am indebted to the late Mrs. Griffiths, of Torquay, for this sponge. She obtained it from one of the trawlers, and it was probably from ‘Torbay. 1g Hymensacipon viripans, Bowerbank. Sponge. Coating; surface even, minutely corrugated, slightly hispid. Oscula slightly elevated and mar- gined, dispersed. Pores inconspicuous, congregated. Dermal membrane spiculous ; spicula abundant, same as those of the skeleton, dispersed or sub-fasciculated. Skeleton. Spicula acuate, moderately stout. Tension spicula acuate, slender, as long as those of the skele- ton. Gemmules spherical, membranous, aspiculous. Colour —Alive, red tinted with green; dried, green ex- ternally, buff yellow internally. Habitat.—Bantry Bay, Rev. A. M. Norman. Examined.—In the dried state. I am indebted to the Rev. A. M. Norman for my know- ledge of this species, He sent me for examination a single specimen in excellent preservation, two and a half inches long, two inches wide, and about four and a half lines in thickness, the external colour being a rather pale but vivid green. The surface was even, but minutely and strikingly corrugated, in the dried sponge; but in the living condition it is probable that the surface would be nearly, if not entirely, free from the corrugations. When a slice from the dermal surface was examined in a little water, with a power of 160 linear, the elevated portions of the corrugations were found to be most abundantly spi- culous, while the depressed parts were each occupied by BRITISH SPONGIADA. 179 several little areas, nearly free from spicula, aud in each of these there were congregated from one to five or six pores, irregular both in size and position. These groups of pores were separated from each other by one or more loose fasci- culations of spicula. The slightly hispid character was pro- duced by the partial projection of portions of these fasciculi, disposed on the sides of the elevated parts of the corruga- tions. A few small groups of pores were visible on the tops of the ridges, but by far the greater number of groups were in the depressed portions of the dermal surface. ‘The oscula were very slightly elevated above the general surface, and their margins were a little thickened and quite smooth. The difference in thickness between the skeleton and ten- sion spicula is not so great as it is in some of the nearly allied species, the diameters of the latter being seldom less than about half that of the former. The gemmules are of a deep red amber colour, and are filled with minute molecules. ‘They vary in diameter from vasth of an inch to ,4nd of an inch, but by far the greater number are about intermediate between these figures. The colour of this sponge renders it very liable to be mis- taken for Halichondria panicea, but a very slight amount of examination will readily separate them from each other. Mr. Norman’s specimens were found on shelving rocks between high- and low-water marks. 19 Hymenractpon peruevis, Bowerbank. SPONGIA PERLEVIS, Montagu. HaticHonpRia PERLEVIS, Johuston. Sponge. Massive, depressed, sessile; upper surface fur- nished with numerous irregular mammeeform pro- cesses. Oscula simple, dispersed. Pores inconspicu- ous. Dermal membrane simple, pellucid, aspiculous, thin. Spicula of the skeleton acuate, sub-fusiform, rarely sub-spinulate. Sarcode abundant. Gemmules membranous, aspiculous, round, or oval. 180 A MONOGRAPH OF THE Colour.—Alive, yellow; dried, buff yellow. Locality—Coast of Devon, Mrs. Griffiths. Examined.—In the dried state. The above description is from the original type specimen of Montagu, in the possession of Professor Grant. The sponge is one and a half inch long, three fourths of an inch wide, and not exceeding half an inch in height. The mam- mzform processes are irregular in form, compressed towards the base, and rarely exceeding two or three lines in height, and internally they are of the same structure as the body of the sponge. ‘The under surface of the sponge is nodulous and uneven, and I could not distinguish the point or points of attachment, if there be any such. The sunken portions of the under surface are furnished with as many oscula as the upper one, where the oscula are dispersed between the bases of the mammeeform processes, and it is evident that the species, in this case, is not a coating one. The spicula present much irregularity of size and form, and are occasionally, but rarely, spinulate ; in the mamme- form processes they radiate irregularly towards the surface, from immediately beneath it, but not in right lines from the axis of the process. In a second specimen in the cabinet of the late Mrs. Griffiths the spicula are somewhat longer than in the type sponge, and the mammeform processes do not appear, but the surface is extremely rugged and uneven. The mamma, as a character, although so striking in the type specimen, can scarcely be considered as necessarily a specific one, and may probably, when we know more of this species, be en- tirely dispensed with. As in the first specimen, there is no distinct base to the sponge, but the under surface is filled with small stones and shells partially imbedded. The spe- cimen has twice the area of the type one, but is not quite so thick. In a third specimen, sent to me for examination in 1859 by the Rev. A. M. Norman, the mammeeform processes were large and numerous, some of them exceeding half an inch in height, and usually had a large terminal osculum, with-a 20. BRITISH SPONGIADA. 181 smooth margin. The rest of the surface of the sponge was exceedingly rugged and full of furrows, and in every other essential character it agreed with the type specimen. It was an inch and a half in length, by about one inch in width, and about three fourths of an inch in height. In Montagu’s specimen there are a few gemmules near the surface of the sponge ; they are of the form so common to the Halichondraceous tribe; membranous, aspiculous, round, or oval, and of a deep amber colour, HYMENIACIDON AUREA, Bowerbank. SPoNnGIA sUREA, Montagu. HaticHonpRia auREA, Fleming and Johnston. Sponge. Sessile, massive, terminating in elongated pro- cesses, or coating. Surface smooth and even. Oscula simple, dispersed, few in number. Pores inconspicu- ous. Dermal membrane abundantly spiculous ; spicula acuate, long, slender, and flexuous. Skeleton. Spicula sub-fusiformi acuate, stout, and long. Tension spicula of interstitial membranes, acuate, long, slender, and flexuous, abundant. Gemmules spherical, mem- branous, aspiculous. Colour.—Alive, orange yellow ; dried, dark brown. Locality.—Estuary of Kingsbridge, Montagu ; Tenby, J. S. Bowerbank ; Bantry Bay, Rev. A. M. Norman. Examined.—lIn the dried state. Montagu’s description of this sponge is exceedingly meager, and embraces only form and colour. Thespecimen is of a compressed form, three inches in length by five-eighths of an inchin breadth, and nearly two inches high to the apices of the elongated processes, some of which exceed an inch in height ; they are from four to six lines in diameter at the base, and taper gradually upwards to a bluntly-pointed ter- mination. 182 A MONOGRAPH OF THE I could find very few oscula by the aid of an inch lens ; they were simple orifices, and were scattered on the broad sides of the sponge. In the live state it is probable that they would be more conspicuous. The pores are very few in number, and were rarely to be seen, even with a power of 250 linear. This may probably arise from the large quantity of dried sarcode with which the membranes are obscured. The dermal membrane is abundantly furnished with spicula, which frequently assume a flat fascicular arrangement near the margins of the oscula. At other parts of it they are dis- tributed without order, as in the interstitial membranes. Montagu has not figured this species, but I have no doubt that the specimen I have described above is the one to which he alludes in his description in ‘ The Memoirs of the Werne- rian Society,’ vol. ii, p. 86. The specimen is now in the pos- session of Dr. Grant, with the original label attached to it. There is a specimen in the British Museum, labelled by Dr. Johnston Halichondria aurea, but it does not belong to the same genus as the sponge described above. It is Isodectya permollis of this work. I dredged up two specimens of this species at 'T'enby, both of them coating oyster shells, but neither of them rising from the base, as in Montagu’s specimen. In colour, both in the living and dead states, they agree completely with Montagu’s type specimen, and in all the anatomical details they cannot be distinguished from each other. With these important cha- racters in unison, the difference in form is scarcely worthy of a consideration. I subsequently received two small specimens of this species from the Rev. A. M. Norman, who found them in Bantry Bay in 1859. In these specimens there were a number of vesicular bodies, which had every appearance of being the gemmules. They were ;¢;th of an inch in diameter when fully developed. The membranous coat of the gem- mules was aspiculous. They were filled with minute vesicular molecules. BRITISH SPONGIADA. 183 21. Hymenractpon armatura, Bowerbank. Sponge. Coating, thin; surface smooth. Oscula simple, dispersed, minute. Pores inconspicuous. Dermal membrane pellucid, abundantly spiculous; spicula cylindrical, sometimes sub-clavate, dispersed or loosely fasciculated. Skeleton. Spicula acuate, stout. Inter- stitial membranes ; tension spicula numerous, same as those of dermal membrane. Internal defensive spicula acuate, entirely spined, few in number. Colour.—Dried, dark red brown. Habitat.—Strangford Lough, Professor Dickie. Examined.—In the dried state. I received this sponge from Professor Dickie, of Queen’s College, Belfast. It covers nearly the whole of the valve of a small Pecten, rather less than an inch and a halfin width, and in its dried state it does not exceed aline in thickness. ‘There are a few small oscula near the margin of the sponge, visible by the assistance of a lens of two inches’ focus, but I could not de- teet a single pore open. ‘I'he dermal membrane is crowded with tension spicula, irregularly dispersed on its surface, and sometimes loosely fasciculated, and they appear to be equally abundant in the interstitial membranes. When fully deve- loped, these spicula are sometimes slightly dilated at their terminations. They are nearly as long as the acuate ske- leton spicula, but only about half their diameter. The internal defensive spicula are sparingly dispersed over the inner surface of the dermal membrane and on the interstitial ones, and were mostly in a recumbent position; they are small, and require a power of about 400 linear to exhibit them well, and without immersion in Canada balsam they are not to be detected in situ. 184 A MONOGRAPH OF THE 22. HYMENIACIDON PACHYDERMA, Bowerbank. Sponge. Massive, sessile; surface corrugated. Oscula small, simple, dispersed. Pores inconspicuous. Der- mis crustular thin, abundantly spiculous; spicula acuate, stout, matted closely together. Dermal mem- brane thin, pellucid, aspiculous. Spicula: of the skeleton, acuate, rather stout and short, occasionally bent near the base; tension spicula acuate, slender, and often sinuous. Colour.—Dried : external, cream colour; internal, light brown. Habitat—Torquay, Mrs. Griffiths. Examined.—In the dried state. I am indebted to my late friend Mrs. Griffiths, of Torquay, for two specimens of this species. Neither of them exceeds an inch in length, by three fourths of an inch in breadth and half an inch in thickness. The surface in each is corru- gated, but much more so in one than in the other; in the remaining characters they agree very closely. The oscula are small, and require the assistance of a two inch lens to render them distinctly visible, and the pores, even with the aid of an inch lens, are inconspicuous. ‘The crustaceous dermis is about the thickness of a stout sheet of letter paper. It is composed of acuate spicula, like those of the skeleton, closely but irregularly interwoven together, and covered with a thin pellucid dermal membrane, in which no spicula are apparent excepting those belonging to the dermis, to which it adheres closely and firmly. ‘The spicula of the skeleton are rather stout, variable in length, and are frequently more or less bent near the base. The slender acuate tension spicula intermixed with those of the skeleton are frequently much attenuated, and are often sinuous. The interior sub- stance of the sponge is permeated in every direction by canals, which are very much larger and more numerous than 23. BRITISH SPONGIADA. 185 might have been expected, from comparison with the size of the oscula and pores. ; The crustular characters of the dermis of the species under consideration and of H. erustula might, on a superficial exa- mination, lead to their being mistaken for each other ; but in H. pachyderma the crustular dermis is comparatively thin, and the skeleton spicula are not more than two fifths the length of those of Hf. crustula. HyMeENIACIDON crustuLA, Bowerbank. Sponge. Massive, sessile. Surface minutely hispid; cor- rugated, occasionally mammillated. Oscula, terminal on the mammille, or dispersed. Pores inconspicuous. Dermis crustular, abundantly spiculous ; spicula same as those of the skeleton. Dermal membrane pellucid, aspiculous. Skeleton, abundantly spiculous; spicula fusiformi-acuate, large, and long. ‘Tension spicula fusiformi-acuate, slender; occasionally sub-spinulate. External defensive spicula sub-fusiformi-acuate, short and slender. Colour.—Alive, buff-yellow or orange-yellow. Hatitat—Scarborough, Mr. Bean; Guernsey, Rev. A. M. Norman; Diamond Ground, Hastings, J. S. Bower- bank. Eeamined.—In the living state. I am indebted to my indefatigable friend Mr. Bean for my first knowledge of this sponge. It was found on the beach at Scarborough, at the latter end of March, 1854. The specimen is irregularly cylindrical in form, with hemi- spherical ends 10 lines in length and 6 lines in thickness, at its greatest diameter. Neither pores nor oscula were visible, and the surface was smooth, the dermal membrane having been destroyed apparently by maceration. 186 A MONOGRAPH OF THE At the latter end of August, 1859, I received two speci- mens of this sponge from the Rev. A. M. Norman, who dredged them up in the neighbourhood of Guernsey. The largest of these was one and three quarters of an inch in length, one and a quarter inch in breadth, and half an inch in thickness ; the smaller one somewhat less in its dimen- sions, but the surface of each was prominently and abun- dantly mammillated, and especially the smaller of the two. In the larger of the two specimens, particularly on the corrugated portions of the surface, the positions of the pores were distinctly visible by the aid of a lens of two inches focus, and with a higher power they presented the appearance of minute pits, but they were not to be detected by the same means on the surface of the smaller of the two specimens. The hispid character is not visible by the aid of a hand lens, but when a section at right angles to the surface is ex- amined with a power of about 100 linear, it is seen to be pro- duced by the projection at about right angles to the surface of an infinite number of small sub-fusiformi-acuate spicula. In the largest of Mr. Norman’s specimens there were two minute oscula in an open condition, on the corrugated surface of the sponge; they were simple circular orifices, with this exception, I could not detect these organs in an open state, but longitudinal and transverse sections of the apices of the mammillz appeared to indicate their position at those points, beyond a reasonable doubt. The pores were also in a closed state, but their positions were indi- cated by the numerous Iittle areas, free or nearly free from spicula, which abound in the dermal tissue. The crustular character of the dermal tissue is not pro- duced by a peculiar arrangement of the organic tissues, but it is caused by a more condensed state of a stratum of the ordinary tissues of the sponge, and in this layer, beneath each of the porous areas, there is an intermarginal cavity to receive and convey the incurrent streams to the interior of the sponge. It 1s not improbable that we may hereafter find that each of the porous areas in the dermal membrane may have BRITISH SPONGIADA. 187 more than a single pore, and in that case the congregation of the pores will become a very important specific character. The existence of these areas and their intermarginal cavities approximates the dermal tissues of this sponge to those of the corresponding parts of the genera Pachymatisma and Geodia. When the sponge, as in Mr. Bean’s specimen, has not a mammillated surface, it may, in the dried con- dition, be readily mistaken for Hymentacidon pachyderma, but the difference is at once obvious when reference is made to the spicula. In the latter species they are not fusiform, and their length is only as two to five of those of the former species. I obtained at Hastings, at the latter end of March, 1863, a still finer specimen of this sponge. It was two and a half inches long, one and a half inches wide, and one inch thick. As in the former cases there were no marks of an attach- ment or base visible, and although a fully matured sponge, there were no appearances of mammuillation on its surface. The oscula at one side were congregated to the amount of twelve or fourteen, but in other parts they were irregularly dispersed. From these circumstances, as compared with those of the previously described specimens, it appears as if there existed a great amount of variation in the external characters of this species. An abundance of gemmules existed in this sponge, at- tached to the parietes of the interstitial cavities. They were globular, membranaceous, and aspiculous, semi- transparent, and filled with distinct granular matter, and they were of a light amber colour. ‘The diameter of a full sized one was , inch. In the living condition the colour of the sponge was a light orange ; when dried, light ochreous yellow, and in the latter state it is very hard and solid. 24. HYMENIACIDON LINGUA, Bowerbank. Sponge. Massive, sessile ; surface somewhat corrugated. Oscula simple, dispersed. Pores inconspicuous. Der- 188 A MONOGRAPH OF THE mal membrane pellucid, furnished abundantly with large spicula, same as those of the skeleton. Skeleton. Spicula abundant, fasciculated, fusiformi-acuate, large and long. Tension spicula acuate, very minute and slender. Retentive spicula bihamate, simple and con- tort, dispersed, minute, very abundant; also dentato- palmate, unequi-anchorate, large and small; large ones congregated in rosette-shaped or globose groups ; occasionally dispersed ; small ones dispersed. Colour.—In spirit and dry, pallid gray. Locality—Western Islands, Scotland, Mr. Archibald McNab ; Outer Skerries and Unst, Shetland, Mr. C. W. Peach. Examined.—In the condition it came from the sea, and preserved in spirit. I received three specimens of this sponge from Mr. Archibald McNab, a fisherman at Inverary. They are of nearly equal size and form, about three inches in length by one and a half inches in width, and from half to three fourths of an inch in thickness; very nearly resembling in form a similar length from the distal end of the tongue of a sheep. When in the undried condition the sponge is exceedingly soft and flaccid, and it was with considerable difficulty I could detect the oscula, in consequence of the collapsed condition of the sponge. It does not contract much in drying, and when in that state it strongly resembles a mass of chopped tow, which has been compressed in the hand while wet and dried in that form. The structure of the skeleton is obscure ; in many parts the spicula, especially towards the edges of the interstitial membranes are so numerous and so closely packed toge- ther as to assume the form of fasciculi, and in some measure that of the skeleton of a Halichondria; but there are no distinct angular junctions forming an irregular network, as in even the most indistinct species of Halichondria. The fusiformi-acuate spicula of the skeleton have many of BRITISH SPONGIADS. 189 them a peculiarity in their form that I have not observed before. From the obtuse base of the spiculum they con- tinue of the same size for the length of six or eight times their own diameter, and then suddenly commence the fusi- form expansion, giving them the appearance of having a handle at the basal extremity. The tension spicula are very minute, and are frequently collected into groups or fasciculi, which contain a considerable number. ‘The con- tort bihamate spicula are dispersed in the sarcode ; they are minute, short, and if not contort would be nearly semi- lunar in form. ‘The anchorate spicula are exceedingly in- teresting ; they are large and stout, the palm at one extre- mity is much expanded, while that at the opposite end is not produced to anything like the same degree. From the constant inequality in the production of these parts of the spiculum, I was led to believe that there must be some peculiar arrangement of these organs, and on carefully examining the inner surface of the dermal membrane, I found my suspicions were correct. ‘They are congregated at distant intervals in radiating circles, containing some- times not more than six or eight spicula, while in other groups they are too numerous to be counted. The groups are usually semi-globose, the smaller ends of the spicula being based on the membrane, but occasionally they become perfectly globose, the proximal ends of the spicula consti- tuting the centre of the group, which then appears to be entirely detached from the membrane beneath. ‘I'he globose congregations of spicula are not nearly so numerous as the rosette-shaped ones. I could not detect any congregations of these spicula on the interstitial membranes, but isolated ones were occasionally found upon them. The smaller variety of anchorate spicula never appear to congregate. The skeleton spicula are exceedingly abundant, and are so massed together as to assume the appearance of large fasciculi, when the membranes are presented to the eye either edgeways or obliquely. The sarcode abounds in globular nucleated cells, which have the surface granulated, or corrugated ; the latter appearance may probably be due to the action of the spirit 190 A MONOGRAPH OF THE in which they have been immersed. Since the above description was written I have received five specimens of this species from my friend Mr. C. W. Peach, they were dredged at Shetland, in 1864. The largest was twelve inches high, six inches broad, an inch thick near one edge, and a quarter of an inch at the middle; one only of the five was as small as the type specimen, and the others of intermediate size, one of them, seven inches in length, was two and a half inches thick near the base. Mr. Peach, in a label attached to the largest specimen, writes: “ This was a thick sponge, very full of glairy matter, and branched, but was cut to pieces by the dredge, and rotted in drying. Very deep water, Outer Skerries and Unst.” The statement of its having been branched must, I think, have been a mistake, as there are no indication of branches on the specimen to which the label was attached, nor any appearance of a tendency to branch in any other of the specimens. This sponge, it is evident, varies greatly in size, but all of them have more or less of a lingual form, and in their anatomical characters they agreed perfectly with the type specimen. 25. HYMENIACIDON FLOREUM, Bowerbank. Sponge. Coating, thin; surface smooth and even. Oscula simple, minute, dispersed. Pores inconspicuous. Dermal membrane pellucid, sparingly furnished with dispersed slender sub-clavate, fusiformi-acuate, tension spicula. Skeleton. Spicula sub-clavate fusiformi-acuate, stout and rather long. ‘Tension spicula of interstitial membranes same as the dermal ones. Retentive spicula dentato-palmate inequi-anchorate, large and _ stout; distal palm, half as long as the spiculum, congregated in numerous radial groups; and bidentate inequi- anchorates few in number, and intermixed in the radial groups; also, deflected and contort bihamate spicula, very large and stout, and few in number; and simple bihamate very minute, and rather numerous. BRITISH SPONGIADA. 191 Colour.—Dried, deep amber colour. Habitat—East Loch, Tarbet, Harris, N.B., 15 fathoms, Captain F, W. L. Thomas, R.N.; Strangford Lough, Pro- fessor Dickie, Queen’s College, Belfast. Examined. —In the dried state. For the first specimen I received of this interesting species I am indebted to the liberality and kindness of my friend Captain Thomas, of the Hydrographical Survey. The sponge covers nearly the whole of the gibbous valve of a specimen of Pecten opercularis, and in the dried state it is scarcely thicker than a sheet of stout writing-paper, and has much the aspect of a layer of dried glue. The surface is uniform and even. A few minute oscula were visible by the aid of a lens of two inches focus, but no traces of the pores could be detected. The interstitial membranes are profusely furnished with skeleton spicula, and when seen edgeways look very like large long sinuous fasciculi of spi- cula. The tension spicula are few in number. The sarcode is abundant, and of a deep amber colour. The prominent feature in this sponge is the striking form and mode of ar- rangement of the retentive spicula, and especially so of the dentato-palmate inequi-anchorate ones, which in this sponge are developed in a more complete and perfect form than I have hitherto seen ; they are in great abundance, and nearly the whole of them are congregated in beautiful rosette- shaped groups, the small or proximal ends of the spicula being clustered together in the centre, while the shafts and distal palms radiate at angles of about 45 degrees from the membrane on which they are seated, the number of spicula in each group varying from six or seven to seventeen or twenty, and sometimes more. On some parts of the mem- branous tissues they are more numerous than on others, and in one case I counted fifteen groups in a circle of rd of an inch in diameter. Occasionally a solitary spiculum of this form may be seen on the membrane, but these single spicula are comparatively few in number. The bidentate inequi- anchorate spicula are much fewer in number than the den- 192 A MONOGRAPH OF THE tato-palmate ones, but they are of the same size, and are indiscriminately mixed with them in the radial groups. The next most remarkable feature in this interesting sponge is the comparatively enormous size of the deflected and contort bihamate spicula, which are of such dimensions that a single one would span a whole group of the anchorate ones ; they are attached by their points to the membrane, while their curved shafts are thrown upward amidst the sar- code. They are very few in number, and are widely dis- persed. The small simple bihamate spicula are much more nume- rous than the large ones, and are as remarkable for their minuteness as the larger ones are for their great size: with- out the aid of a power of about 400 linear, they can scarcely be detected cx setu, although the specimen be immersed in Canada balsam, and it must be remembered that without this mode of preparation even the radial groups will not be- come visible. I subsequently received a second specimen of this sponge from Professor Dickie, of Queen’s College, Belfast, and this one also was on a shell of Pecten opercularis. It occupied about half an inch in width of the whole front of the shell, while the remainder of the valve was covered with Hali- chondria nigricans. ‘he essential characters of this speci- men of Hymeniacidon floreum were in accordance with those of the first, but in the part examined the rosette-like groups of spicula were very few in number. The specimen being young and very thin may probably account for the difference between the two in this respect. There are some peculiarities in this species which might readily mislead a hasty observer into the belief that it was a variety in form of Hymeniacidon lingua. Thus the strikingly characteristic groups of retentive spicula resemble each other in both form and mode of arrangement so closely that if it were not that they are rather less than half the diameter in H. floreum, of those in H. lingua, it would be difficult to distinguish one from the other. ‘The spicula of the skeleton also rather closely resemble each other, but. those of H. floreum differ from the skeleton spicula of H. lingua in BRITISH SPONGIADA. 193 being not more than half the length and diameter of the latter, and in the basal end being somewhat clavate, which is not the case in H. lingua. In other points the specific differences arg very decided and effective. 96, HYMENIACIDON VIRGULTOSA, Bowerbank. HaLicHonDRIA VIRGULTOSA, Johustozn. Sponge. Parasitical, coating Zoophytes or Fuci, elongate or virgultose, more or less compressed ; surface smooth. Oscula and pores inconspicuous. Dermal membrane pellucid, spiculous, furnished abundantly with minute inflato-cylindrical spicula, irregularly dispersed. Skele- ton. Spicula acuate, long, very rarely sub-spinulate. Interstitial membranes attenuato-acuate, long and slender, and rarely with minute inflato-cylindrical spicula. Colour.—Dried, light buff yellow. Habitat—Dogger Bank, Mr. Peter Cullen. Ezamined.—In the dried. state. The type specimen of this species, described by Dr. Johnston, in his ‘ History of British Sponges,’ page 137, is in the possession of Mr. Bean, of Scarborough, where I have had the pleasure of seeing it. The form of the specimen, before it was broken, was thatof a slender, irregular cylinder, somewhat compressed and slightly twisted ; it was about fifteen inches in length, and nearly half an inch in diameter. At the same period I obtained from Mr. Peter Cullen a series of the species of five specimens. ‘The whole of these were from eight to eleven lines wide, and from two to five lines thick ; the shortest was two inches and three quarters long, and the largest ten inches and three quarters in height, and the whole of them preserved nearly the same proportions from base to apex. There was also more or less of the appearance of a suture, running nearly the whole length of 13 194 A MONOGRAPH OF THE the sponge, from the proximal to the distal extremity, and occasionally there were short portions of its length which were not entirely closed. ‘These sutures appear to me to be the results of the parasi- tical habit of the species, as in one of them I found the remains of a tubular, horny Zoophyte at the base, and at very near the apex of the sponge, immediately on the line of the longitudinal suture, evidently extending from the base to the point near the apex where the Zoophyte emerged from the sponge, and in another specimen small portions of the included bodies projected occasionally from its surface, but were broken close off, apparently after the sponge had been dried. In two of the specimens also the impressions of the included Fuci or Zoophytes were distinctly apparent on the surface of the sponges. Mr. Bean has also a series of specimens similar to those I have described, which were obtained from Mr. Cullen, who informed me that the whole of them were dredged by the trawlers at the Dogger Bank, from which locality it is very probable that the type specimen of Halichondria virgultosa (Johnston) in Mr. Bean’s cabinet was obtained. Three of myspecimens had their basal attachments perfect, and in each the substance from which they sprung was a dentalium, and in each case there was not the slightest tendency to lateral expansion of their bases ; and the general habit was evidently that of closely embracing and lapping, as it were, their supporters, entirely within their substance. Their course was directly upwards, and not the slightest disposition to branching was evinced by either of them, not even as in the onewhere the includedhorny Zoophyte emerged from its broadside. _ The dermal membrane is thin and pellucid, and crowded with minute inflato-cylindrical spicula, which are thickly matted together. 'The inflation in these spicula is not always at the middle of the shaft ; in this respect it varies consider- ably, in some approaching very nearly one of the terminations of the spiculum, Although so abundant in the dermal mem- brane, they are of rare occurrence in the interstitial ones. BRITISH SPONGIADA. 195 Dr. Johnston believed that this species was identical with Lamarck’s Spongia virgultosa, but I regret that I cannot agree with him in that opinion. The learned author of the ‘ History of the British Sponges’ states that he had seen only frag- ments of the species from the collection of Mr. Bean, and I feel satisfied that had he seen Mr. Bean’s type sponge, and had obtained five specimens of the same species as I have, he would have entertained a different opinion on the subject. The species described by Lamarck in the second edition of ‘ Anim. s. Vert.,’ page 565, is characterised as follows :— “§. stipite duro, erecto, ramoso ; ramis subteribus, virgatis erectis, acutius culis; superficie pannea;’ and Lamarck then refers to Esper, Suppl. 2, table 66, than which nothing can well be more unlike to our sponge. Nor does Lamarck’s description at all agree with the British specimen, which has no stem, and no appearance of branches, and has no tendency to terminate acutely. On the contrary, the distal end is usually rather broader than the proximal one, and the surface of all the specimens I have seen are quite smooth, instead of being ragged, as Lamarck’s sponge is said to be. LEsper’s figure, without reference to anatomical characters, will serve to represent numerous other similarly ramose species beside the one for which it was originally designed, and the same may be said of Lamarck’s description, based entirely on external characters. I have, therefore, thought it advisable to retain the specific name Virgultosa for the British species, as established by Dz. Johnston. 27.HYMENIACIDON PLUMOSA, Bowerbank. Sronela prumosa, Montagu. HaticHonpsia Poumosa, Johnston. Sponge. Sessile, upper surface rugose and mammillated. Dermal membrane pellucid, furnished with flat fasci- culi of large acerate spicula; and minute dentato- palmate angulated anchorate, retentive spicula ; occa- sionally arranged in circular groups, and attached by 196 A MONOGRAPH OF THE one end only. Oscula simple, large, abundant, dis- persed. Pores inconspicuous. Skeleton: spicula acuate, entirely spined, stout ; and occasionally without spines. Internal defensive spicula attenuato-acuate, entirely spined. Interstitial membranes. ‘l'ension spicula like those of the dermal membrane ; and with attenuato-acuate entirely spined defensive spicula; retentive spicula like those of dermal membrane, very abundant. Colour.—Alive, scarlet; when dried, light yellow. Locality—Coast of Devonshire, Montagu and Mrs. Griffiths. Examined.—lIn the dried state. The anatomical structure of this sponge is very interest- ing. The skeleton is exceedingly diffusive. The plumose appearance at the surface of the sponge in Montagu’s type specimen is produced by the projection of a few of the terminal fasciculi of the skeleton, partially enclosed within the dermal membrane and projecting above the surface, in some cases to the extent of three or four lines; but this is not the natural condition of the sponge. Montagu’s specimen has been very much weathered, and a considerable portion of the dermal membrane has been destroyed, but fortunately for our knowledge of this species my kind friend, the late Mrs. Griffiths, of ‘Torquay, who assi- duously collected and studied the British sponges for many years, has, with her accustomed liberality, sent me the whole of her valuable collection for examination, and among them there are three specimens in a fine state of preservation, having the surface thickly studded with mammillated elevations, which are entirely enclosed by the dermal membrane, and which therefore do not possess the plumose character, whence the name is derived by Montagu. The dermal membrane is pellucid, and is, comparatively, of considerable thickness, and very similar to the general mass of the interstitial membranes. It is abundantly furnished with flat bundles of numerous large acerate BRITISH SPONGIADA. 197 spicula, without spines, and with a considerable number of dispersed minute angulated dentato-palmate, anchorate, retentive spicula, which are generally attached by the middle of the back of the bow of the spiculum to the inner surface of the membrane. In one small portion of” the dermal membrane the anchorate spicula were arranged in a circular group, one end of each spiculum being inserted in the inner surface of the membrane, and the remainder of the spiculum being projected from its plane at about an angle of 45°, the whole forming a beautiful rosette-shaped. group, similar in appearance to the grouping of the like description of spiculain Hymeniacidon lingua ; but although I examined many other small portions of the dermal mem- brane of the same specimen, I did not meet with a second case of the same mode of arrangement. It is the first time that I have met with this singular form of spiculum, in which the bend of each of the hooks appears as if each side of. the hook had been forcibly compressed towards the other, so as to form an angulated hook instead of a regularly curved one. ‘The skeleton is rather slender, and is composed of closely packed acuate spined, and acerate unspined spicula, the latter being the same as those of the dermal membrane, but the defensive spicula of the skeleton ‘consists of entirely spined acuate spicula, the bases being inserted about once or twice the length of the diameter of the spiculum in the membrane, and the rest of the spiculum projecting at or very near to right angles. The interstitial membranes are abundantly but irregularly furnished with the three descriptions of spicula, and are very frequently armed with the spined acuate spicula, in the same manner as the skeleton ; among the spined spicula are many which are shorter and more attenuated than the others, and these appear to be truly the defensive spicula, but in this curious species both the large and the small acuate, spined spicula are projected indifferently and in great profusion from all parts of the membranes. The third specimen sent me by Mrs. Griffiths was labelled “Scarlet Foetid Sponge.” I presume, therefore, that in its living state, that is, its natural colour, it is found, according 198 A MONOGRAPH OF THE to the same authority, “on the rocks, at the lowest spring tides only.” 9g HymeEntacipon secuscuLtum, Bowerbank.. Sponge. Coating ; surface corrugated, slightly hispid. Os- cula simple, dispersed: submarginated, shghtly ciliated. Pores inconspicuous. Dermal membrane pellucid, abundantly spiculous; spicula acerate, long, and slender; inner surface furnished with numerous stout angulated, equi-anchorate, retentive spicula. Skeleton : spicula attenuato-acuate, basally spined, long and stout, occasionally subclavate ; spines rather short and small. Internal defensive spicula attenuato-acuate, entirely spined ; short, occasionally subclavate ; spines large and long. External defensive spicula -acerate, like those of the dermal membrane. Spicula of inter- stitial membranes acerate, long, and slender, sometimes flexuous, numerous. Retentive spicula, angulated, bidentate, equi-anchorate, rarely tridentate,-large; end stout, exceedingly numerous, ‘ Coiour.—Alive, vermilion-red ; dried, dark flésh-red.-- Habitat.—Caves, Island of Harris, Hebrides ; Capt. F: W. L. Thomas, R.N. 4 Ezxamined.—In the dried state. Ze I am indebted to my friend Captain Thomas, of the Hydrographical Survey, for this new and interesting species, which he found on the side of a cave on the coast of the Island of Harris, at low water spring tide. In its present dried condition it is one inch and a half in length, three fourths of an inch in breadth, and four lines in thickness, and in colour and appearance very closely resembles a thin slice of sun-dried muscle of beef or mutton; but when alive, my friend states it is of a pure vermilion-red colour. ‘The surface is irregularly corrugated, and the corrugation appears to be produced principally by the slightly elevated BRITISH SPONGIADA. 199 state of the oscula. When examined by direct light, with a power of about 100 linear, it is seen to be minutely hispid; but it is very probable that both this character and the corrugations may not exist in the living sponge. Although not a single osculum could be detected in an open condition, these organs were readily to be distinguished in the dried specimen by their slightly elevated and rounded margins and depressed areas, and by the projection from the inner side of the marginal ring of a delicate ciliary fringe of spicula, inclining inward at an angle of about 90°. When a thin slice of the dermal surface is mounted in Canada balsam, and examined by transmitted light with a power of 160 linear, this ciliary fringe is seen to be pro- duced by the protrusion of the proximal ends of a converging circle of closely packed parallel spicula, of the same size and form as those of the surrounding dermal membrane ; and in the central depressed area the closed membrane of the osculum, with a few retentive spicula only, on its inner surface, is to be seen. The remainder of the spicula of the dermal membrane are dispersed without any approximation to order; and its internal surface is literally crowded with retentive spicula. The skeleton spicula are not nearly so numerous as those of the interstitial membranes. The length of the two is nearly equal, but the latter is not more than half the greatest diameter of the former. Their spination is frequently confined to very near the basal extremity, while in others it extends to about the middle of the shaft of the spiculum. The internal defensive spicula, although of the same form, are readily to be distinguished from the skeleton ones, by their smaller size, their entire spination, and by the much greater comparative size and length of their spines; both descriptions of spicula frequently appear to be subclavate at the basal extremity, but this character appears to be due rather to profuse spination than to distension of the bases of the spicula. The interstitial membranes are profusely furnished with both tension and retentive spicula. The former are frequently congregated in loose and irregularly disposed 29. 200 A MONOGRAPH OF THE fasciculi, but the latter are always in a dispersed con- dition. © I subsequently received a second specimen of this sponge from Captain Thomas, from the same locality. He describes it as “about four inches over, and three or four lines thick ; the colour was pure vermilion, the surface smooth and shining, apparently without oscula, the substance firm and. fleshy on fracture. ‘The general appearance of the sponge when fresh is like a piece of fowl’s liver.” HYMENIACIDON SUBEREA, Bowerbank. Sponeta sUBERIA, Montagu. HaLicHONDRIA SUBERICA Fleming. — SUBEREA, Johnston. Sponge. Sessile, coating, or massive ; compact and fleshy. Surface smooth and even, with terminations of spicula occasionally projecting through it. Oscula in young specimens often inconspicuous; in mature ones large, simple, and few in number. Pores inconspicuous. Dermal membrane pellucid, aspiculous. Skeleton: spicula fusiformi-spinulate, variable in size and tenuity ; gathered more or less into expanding fasciculi as they approach the surface. Colour.—Alive, yellow or orange; dried, yellow or brown. Locality.—The whole of the British coasts. Examined.—In the living and dried state. A careful examination is required to distinguish accu- rately between this species and H. carnosa. In large massive specimens, or when coating shells, it may usually be safely concluded that the sponge will prove to be Z. suberea, but when it happens to have been based on a Denta- hum,a Vermetus, or some other equallyill-chosen locality, not affording it surface for basal expansion, it frequently assumes very much the pedestalled lobular form of H. carnosa. Nor does a microscopical examination immediately solve BRITISH SPONGIADA. 201 the difficulty, as there is a striking similarity of form be- tween the spicula of the two species under consideration ; but although this close approximation in form exists there is so great a difference in their proportions as to render their ultimate separation distinct and certain; s0 much so that an experienced observer may readily determine the species by the spicula alone. The following measurements derived from the spicula of the type specimens of the two species in the Johnstonian collection in the British Museum, will best illustrate their differential characters. One of the largest spicula from #. carnosa measured 3th inch in length, and ,.:nd inch in diameter. An average-sized one was 3th inch long, and ,2,th inch greatest diameter, while in H. suderea, one of the longest spicula I could find measured ;th inch in length, and ;3,rd inch in diameter, and an average-sized one ,3,rd inch long, and ;3,th inch ‘greatest diameter. ‘I have examined a considerable number of specimens of each species, and I have found their pro- ' portional differences to exist in every case. In both sponges the spicula are subject to malformation and of irregularities in the development of the spinulate bases, and therefore the differences in their proportions become the more valuable as differential characters. ‘ A favorite locality of H. suderea is on the shells of various species of Turbo, Fusus, and other univalves, which it often entirely envelopes, intruding itself frequently far into the interior of the shell, although it may be also occupied by a Pagurus. In a specimen assuming the form of a compressed Hymeniacidon ficus, and of about or rather larger than the usual size of that species, partially enveloping a shell of a Fusus, the mollusc was evidently alive at the time of the sponge locating itself, as the whole of the face of the shell, from the apex of the whorls to the extreme point of the canal for the passage of the siphuncle of the mollusc, is perfectly clear of the sponge, while the whole of the back of the shell is as completely covered by it; but notwithstanding that it does not at any part pass over the edge of the shell, it has not succeeded in gaining possession of the interior within the last whorl for nearly an inch, 202 A MONOGRAPH OF THE there is an extremely thin layer of the sponge looking like dust within the mouth of the shell, and the angle within the shell at the junction of the outer with the inner whorl, is filled up to the breadth of about a line, and the depth of half a line. From this it would appear that every minute fragment of the sarcode of the sponge, although separated from the parent mass, is capable of sustaining the life it carries with it, and of multiplying the species by even this minute mode of division. This mode of developing itself from a univalve shell is also the habit of H. ficus, which is by no means uncommon, from the north-eastern coasts of England. There is one of this description, based on the shell of a Fucus, that is in the Museum at Newcastle-on-Tyne, which is projected in an elongated flattened form to the length of seven and a half inches, having several large lateral lobes, and not exceeding an inch in thickness at any point, each lobe having one or more oscula, the whole number of these organs being twelve or thirteen, none of them exceeding the eighth of an inch in diameter; but the difference between the two species is readily determined by the presence in A. jicus of the minute inflato-cylindrical, which abound on the inner surface of its dermal membrane. In the neighbourhood of Tenby H. suderea is frequently brought up by the oyster-dredgers, in masses as large as a man’s fist, without any appearance of shell, which has pro- bably been entirely enclosed by the sponge; in these speci- mens two or three large oscula are usually found, and the sponges are generally of a rich orange colour. I also found a specimen as large as a hen’s egg, attached by a broad base to the side of St. Katherine’s Rock, at Tenby, between high and low water mark, showing that it is occasionally a littoral as well as a deep-sea species; but I have usually found it on dredging in from 5 to 15 fathoms. BRITISH SPONGIADZ. 2038 30, HyMENIACIDON caRNOSA, Bowerbank. HaticHonpria carnosa, Johnston, Sponge. Sessile or pedicelled, round or fig-shaped, com- pact and fleshy. Surface even, minutely hispid. Oscula and pores inconspicuous. Dermal membrane aspiculous. Skeleton spicula spinulate, long and slender. External defensive spicula same as those of the skeleton ; dispersed in minute divergent groups. Tension spicula spinulate, long and slender. Gem- mules spherical, membranous, aspiculous. Colour.—Alive, buff or yellow to red-brown. Locality.—Coasts of Ireland, Weymouth Bay, J. 8. Bowerbank ; Plymouth, Mr. J. H. Stewart; Durie Voe, Shetland, Bantry Bay, Rev. A. M. Norman. Examined,—In the fresh and dried states. The general description of this sponge by Dr. Johnston is accurate, with a few exceptions. That author states that “the spicula are minute, and lie principally in parallel fascicles in the animal matrix.’”” This description of the dis- position of the spicula is correct only at the immediate sur- face of the sponge and for the depth of two or three times the length of a spiculum ; in all the rest of the mass the spicula are loosely matted together without any approach to regularity of disposition. At the surface, for the brief space I have mentioned, they are collected into short bundles, the outer terminations of which project about half the length of a spiculum in a divergent manner, so that when the surface of the sponge is examined with a power of 200 linear it presents a series of groups of radiating spicula, which are nearly equidistant, but with no appearance of pores between them, while a similar slice from the surface of Hymeniacidon suberea ex- hibits numerous pores, and the spicula projected through the surface, though congregated in bundles as in Z7. carnosa, are not projected to so great an extent. The substance of H. suberea is also more dense immediately beneath the 204 A MONOGRAPH OF THE dermal membrane, so as to give it the appearance to the eye of having a tolerably thick dermis, while in H. carnosa there is no such perceptible thickening at that part, and, in fact, » in neither of the species is the dermal membrane readily apparent, even beneath a power of 160 linear, when sec- tioned at right angles to its surface. On dividing three specimens of H. carnosa, which had been preserved when alive in a saturated solution of bay salt, I could not with the unassisted eye perceive any of the canals, while in a similar selection of specimens of H. suberea they were numerous and distinctly visible. It is necessary to be thus particular in the description of the differential character of the two species, as in other re- spects they agree remarkably in their structure; thus the form and disposition of the spicula of the skeletons in LT. carnosa and H. suberea are scarcely distinguishable, and the external form and general texture are frequently very like each other. In many of the species of Hymeniacidon the tension spicula of the membranes are of the same form and length as those of the skeleton, but very much more slender in their proportions; the same difference appears to prevail in those of ff. carnosa. The stout or skeleton spicula vary greatly in length, but they have their globular bases usually well developed and at the extreme end of the shaft; but occa- sionally, though rarely, the globular base is placed at about one or two diameters of the shaft beyond its extreme end, which then terminates hemispherically, and the spicu- lum becomes enormi-spinulate; but in the slender—or what we may term by analogy the spicula of the interstitial membranes—the development of the base is by ho means so uniform; sometimes half of it only is produced laterally, or it terminates the spiculum ina reversed cup form, and in some cases a secondary bulb is partially formed immedi- ately beneath the primary one, and both are frequently more or less imperfect. 'lhese variations and malformations, which arise apparently from imperfect development, prevail more or less also in many specimens of ZZ. sudereu that 1 have seen. BRITISH SPONGIADA. 205 I have carefully examined the type specimen of Dr. Johnston’s Halichondria carnosa, which is in the British Museum, and I find that the spicula of the skeleton, although agreeing in form with those of H. suderea, are pro- portionally much more slender and considerably longer, but as I have entered fully into the details of these characteristic differences existing between the two species, I will not repeat them here, but refer the student to my account of them in the description of the differential characters of the two species under consideration as the best mode of discriminat- ing them under doubtful circumstances. I am indebted to my late friend, Mr. John Howard Stewart, of the Royal College of Surgeons, for four speci- mens of this species on a broken shell of Pecten opercularis. Two are about half an inch in diameter, one about two lines, and the fourth very little more than a line. They are all nearly globular, and completely sessile. Another specimen from the same gentleman is also sessile, the base embracing the point of a Dentalium. In a pear-shaped specimen, ten lines in height and eight in diameter, that I received for examination from the Rev.. A. M. Norman, there were an abundance of dark amber- coloured spherical vesicles, filled with round or oval mole- cules; the whole mass of the sponge, excepting a space about equal to the length of a skeleton spiculum below the dermal membrane, appeared to be crowded with them. They were dispersed without any approach to order, and the fully-developed ones were nearly of the same size; an average-sized one of this description measured ;A,th of an inch in diameter. The parietes of the vesicle consists of a simple, strong, transparent, aspiculous membrane, and each of the molecules within it appeared to have a distinct trans- parent membranous envelope. I could not with a linear power of nearly 600 detect a foramen in any of these vesicles, but from their structure and mode of disposition within the sponge I have no doubt of their being its reproductive gemmules. The Rev. A. M. Norman found this species at Durie Voe, Shetland. He says: “The amount of animal matter in 206 A MONOGRAPH OF THE this sponge is far greater than in any other species with which Iam acquainted. The specimen sent is a very small one. It attains the dimensions of a good-sized apple. When alive it is of a red-brown colour, and lives on very muddy ground.” Specimens of Hymeniacidon ficus are often, when young, very like those of H. carnosa, but they may be readily distin- guished by the minute inflato-cylindrical spieula which abound in their dermal membranes. 31. Hymentacipon Ficus, Bowerbank. Haticuonpr1 Ficus, Johnston. Sponge. Massive, sessile, or pedicelled, rarely coating. Oscula simple, few, and scattered. Pores inconspicu- ous. Dermal membrane thin, pellucid, minutely granulated, abundantly supplied with minute inflato- cylindrical spicula, irregularly dispersed. Skeleton. Spicula, spinulate and acuate, the former exceeding the latter im number. Interstitial membranes. Spicula sub-attenuato-acuate, long, slender, numerous. Colour.—Alive, gray, white, or russet red. Habitat—Coast of Scotland, Mr. W. C. Peach; Coast of Northumberland, Rev. A.M. Norman ; Island of Harris, Hebrides, Capt. Thomas. Examined.—In the living and dried states. The ficoid type of this species has been so accurately described by Dr. Johnston, in his ‘ History of British Sponges,’ as to leave little more to be said on that part of its history ; but, like many other British species, it varies so greatly in form as to render it very difficult, if not im- possible, to distinguish it by this character alone from other nearly allied species; thus, I have a little specimen which has completely covered a small univalve shell precisely after the manner of H. suwberea, and without exhibiting the BRITISH SPONGIADA. 207 slightest indication of either a bulb or the pedicel for one. H. suberea also frequently simulates the bulbous form of H, ficus so exactly as to render it impossible to distinguish the species of either sponge by form alone, but the cha- racters of the spicula, seen with a power of about 200 linear, will readily settle the question. In its most perfect state of development it has usually a short stout pedestal, and the mass of the sponge assumes the form of a compressed dried fig. I have received this species from the Island of Harris, in the Hebrides, from my friend Captain Thomas, R.N., coating evenly the greater portion of one valve of Pecten opercularis. He states that “when dredged it was two tenths of an inch thick, and had a russet tinge.” In its dried condition its thickness scarcely exceeds that of stout writing-paper. Thus in the discrimination of this species very little dependence can be placed in form as a specific character. The skeleton spicula of H. jicus are mostly acuate, but occasionally they are more or less inclined to assume a spinulate form. ‘The dermal membrane is abundantly sup- plied with minute, slightly curved, cylindrical spicula, having each a bulbous inflation near the middle. The position of this inflation varies considerably ; sometimes it 1s equidis- tant from the ends of the spiculum, and at others it is about a third of the length of the spiculum from one end. A power of 500 linear is required to show them well. The interstitial membranes are also more sparingly supplied with the same form of spiculum, but varying more in size than those of the dermal membrane; some of the larger ones are bluntly acerate. No oscula were apparent on any part of the surface of a wet specimen in my possession ; in others, which have been dried, they are few, minute, and scattered, and very rarely attain a diameter of two or three lines. When the dermal membrane is in a fine state of preservation, it is covered with closely packed minute gra- nules, which require a power of not less than 300 linear to be well displayed. These minute organs were also ob- served in the canal membranes of one of my ficoid speci- mens, but I could not see them so satisfactorily in the dermal 208 A MONOGRAPH OF THE membrane, probably in consequence of the washing it had undergone previous to being dried for the cabinet. They require a microscopic power of 300 or 400 linear to define them ina satisfactory manner when 7x situ. The occurrence of the inflato-cylindrical spicula in the dermal membrane of this species might lead a hasty ob- server to imagine the specimen a variety of H. virgultosa, but the difference in the form of the skeleton spicula will readily distinguish them. In the latter sponge both skele- ton and tension spicula are acuate, while in H. ficus the skeleton ones are spinulate, and the tension spicula more or less attenuated acuate. From the great size of the latter it naturally leads to the supposition that the skeleton spicula are of two forms, instead of being all spinulate. 32. HYMENIACIDON SULPHUREA, Bowerbank. HALICHONDRIA SULPHUREA, Bean, MS. Sponge. Coating, surface smooth and even. Oscula and pores inconspicuous. Dermal membrane _pellucid, abundantly spiculous. Spicula spinulate, large and long, and very small, numerous, irregularly and thickly matted together. Skeleton. Spicula spinulate, stouter and shorter than those of the dermal membrane, very numerous. Colour.—Dried, sulphur-yellow. Locality—Scarborough, Mr. Bean ; Guernsey, Rev. A. M. Norman. Examined.—In the dried state. This sponge covers the surface of the sandstone on which it is based for about two square inches, following its irre- gularities, and in no part exceeding half a line in thickness when dried. A few scattered orifices were apparent with a half inch lens, probably oscula. When a portion of the dermal membrane was viewed as a transparent object, with BRITISH SPONGIADS. 209 a power of 660 linear, it presented a remarkably imperforate appearance, the pores being rarely visible. ‘he dermal membrane is not a mere film, but has comparatively a con- siderable amount of thickness, and is thickly coated in- ternally with spinulate spicula, closely felted, as it were, together, interspersed with which there are numerous minute ones of the same form. The spicula of the interstitial membranes are of the same form as those of the dermal one, but somewhat stouter and shorter in their propoftions, and they are not quite so numerous, although very abundant, and the minute spinulate ones are not by any means so abundant. ‘The sarcode presents the appearance of a firm amber coloured jelly, of uniform consistence, when viewed with a power of 400 linear. The specimen sent to me by my friend Mr. Bean, was labelled Halichondria sulphurea, and I have therefore adopted his very appropriate name, as in its dried condition it causes the stone which it coats to appear as if it had been washed over with a thick infusion of milk of sulphur. The Rev. A. M. Norman subsequently sent me a speci- men of this species from Guernsey, which covered part of the shell of an oyster to about the same degree of thickness as that of the type specimen, with which it also agreed in every other respect. 388. HyMENIACIDON sUBCLAVATA, Bowerbank. Sponge. Coating. Surface even, smooth. Oscula simple, dispersed. Pores inconspicuous. Derma] membrane abundantly spiculous ; spicula sub-fasciculated, fusi- formi-sub-clavate, rarely acuate, slender and frequently flexuous, about as long as those of the skeleton. Skele- ton: spicula fusiformi-sub-clavate, rarely purely acuate, stout, and moderately long. Retentive spicula, con- tort bihamate, large and slender, very numerous, and bidentate inequi-anchorate, very minute; and rarely dentato-palmate inequi-anchorate. 14 210 A MONOGRAPH OF THE Colour.— Alive, pale flesh-red ; dried, dull buff-yellow. Habitat.—Tenby, on oyster-shells and stones. Examined.—Alive and dried. This species is by no means uncommon on the shells of the large oysters dredged at Tenby, frequently extending over the whole surface of the valve, but rarely exceeding three or four lines in thickness. The oscula in many of the living sponges were not visible, but in some of the dried specimens they were readily seen by the assistance of a lens of two inches focus; the largest observed did not exceed about a line in diameter. In the dermal membrane there is a manifest tendency to fasciculation of the tension spicula, but there are no symptoms of order or arrangement of these loose bundles. In both the skeleton and tension spicula there is a constant tendency to sub-clavation of the base of the spiculum, and perhaps more especially among the tension ones ; but in none of them is the clavate termination strongly produced: but this tendency to dilatation of the base of the spiculum is decidedly the rule, and the occurrence of purely acuate forms the exception. The retentive spicula are abundant, and very characteristic. The bihamate ones are large and very numerous ; in a full developed state they measured .3; inch in length. The bidentate anchorate ones are also rather numerous, but exceedingly minute; one of the largest of them measured xz Inch in length. They are perfectly invisible in the fresh tissues, and are rarely to be detected im situ, even by the aid of Canada balsam, and it is only by preparation in boiling nitric acid, and with a microscopic power of about 800 linear, that they can be satisfactorily defined. The occurrence of the dentato-palmate inequi-anchorate ones is rather rare. A fine specimen which I measured was y3 inch in length. BRITISH SPONGIADA. 211 34. HyMENIACIDON CLAVIGERA, Bowerbank. Sponge. Massive, sessile? Surface uneven, deeply pitted, more or less hispid. Oscula and pores unknown. Dermal membrane thin, pellucid, spiculous; spicula same as those of the skeleton. Skeleton: spicula at- tenuato-clavate or spinulate, large and very long, variable in size, often more or less flexuous. Internal defensive spicula, attenuato-clavate, entirely spined, variable in size ; clavate terminations mostly exaxial, frequently large and long; spines numerous, small. Sarcode abundant, amber coloured. Colour.—Dried, light gray. Locality.—Firth of Clyde, Rev. A. M. Norman. Eeamined.—In the dried state. This species is described from a very incomplete and un- satisfactory specimen, which is apparently a portion only of the perfect sponge ; but the characters, as far as they go, are very distinct from those of any other species of the genus. The specimen is nine lines in length, and about four lines in thickness and breadth. The characters of the surface are much obscured by an abundant growth of a Mucor, and I could not detect either oscula or pores. In the living state it is probable that the surface would neither be deeply pitted nor hispid. The spicula of this sponge present excellent specific characters. Those of the skeleton are spineless, and are frequently very long and slender, and they are abundantly ‘dispersed on the interstitial membranes ; they are variable in size, and often flexuous. ‘The basal enlargement most frequently presents a more or less clavate form, but occa- sionally they are cylindrical. The internal defensive spicula are also exceedingly variable in length and thickness, and the clavate base is mostly exaxial, the deflexion frequently being toa very considerable extent. The spines are abun- 212 A MONOGRAPH OF THE dantly dispersed over the whole length of the spiculum, but are very short and fine. These spicula are very numerous, and they are projected in every direction into the interstitial cavities of the sponge. 1 am indebted for my knowledge of this species to the Rev. A. M. Norman, of Newbottle, Co, Durham. 85. HymeEniacrpon cEeLata, Bowerbank. CLIONA CELATA, Grant. — A. Hancock. Annals and Mag. Nat. Hist., N.S. vol. iii, p. 332. Goreonipzs, 4. Hancock. Ibid., p. 333. GRACILIS, 4. Hancock. Ibid., p. 334. Howse1, 4. Hancock. Ibid., p. 336. Norruumsrica, 4. Hancock. Ibid., p. 336. ALpDERI, 4. Hancock. Ibid., p. 387. coRaLuinorpEs, 4. Hancock. Ibid., p. 337. topata, 4. Hancock. Ibid., p. 341. vastiFica, 4. Hancock. Ibid., p. 342. HaALICHONDRIA CELATA, Johnston. aaron Sponge. Inhabiting perforations and hollow spaces in oyster and other shells, and limestone rocks and boulders. Surface smooth. Oscula simple, or slightly elevated. Pores inconspicuous. Dermal membrane pellucid, abundantly spiculous ; spicula same as those of the skeleton. Skeleton: spicula sub-fusiformi- enormi-spinulate, variable in length and mode of spi- nulation. Sarcode abundant, yellow to dark-amber colour. Colour.—Alive, yellow, or amber colour. Habitat—All parts of the coast of Great Britain in oyster and other shells, and in the limestone rocks of Tenby in abundance. Examined —In the living state. This sponge is one of the simplest in its anatomical structure of all the British species. In the dried condition BRITISH SPONGIADA. 213 it separates spontaneously, by contraction, from the sides of the canals which it generally inhabits, and its surface, when examined beneath the microscope, appears perfectly smooth and even. The dermal membrane, in its structure, does not appear to differ in any respect from the interstitial one, both membranes being abundantly supplied with the spicula of the skeleton. The form of the base of the spiculum varies considerably in the same individual; some are regularly oval, others ovate, but the greater number of the adult ones are more or less enormi-spinulate. In some specimens the amount of variation from the normal form is greater than in others ; but in none of them do the varieties exist to so great an extent as to induce us to accept them as the normal form of the sponge spiculum. The young spicula are frequently acuate, and they may be seen passing through every gra- dational development up to the well-produced adult enormi- spinulate form. The sponge projects for about a line and half from each of the external terminations of the excavated canals, and each of these projections is furnished with an osculum. These organs have been so ably and accurately described by Dr. Grant, in the ‘ Edinburgh New Phil. Journal,’ vol. i, p. 78, and vol. ii, p. 183, that I cannot do better than quote his description of them. “The projecting tubular papilla possess a complicated structure and a high degree of contractile power, and exhibit a singular series of ap- pearances when the Zoophyte is attentively examined while at rest in pure sea water. When under water, the papille are seen projecting from the apertures of the shell, some- times to the length of a line and a half; they present a wide, circular opening in their centre, and a rapid current of water issues constantly from them, conveying, occasion- ally, flocculi of a gray, membranous matter. But on being touched with a needle, or withdrawn from the water, the opening gradually closes, the current ceases, and the whole papilla, continuing slowly to contract, is withdrawn com- pletely within the aperture of the shell. The papilla, viewed in their contracted state, present a smooth, rounded, 214 A MONOGRAPH OF THE short extremity ; but when they begin to advance beyond the surface of the shell, their extremity becomes flat and slightly dilated, assumes a villous appearance, with open fissures, radiating from the centre to the margin of the papilla, and at length a minute circular opening is perceived in the centre of the villous surface. ‘The papilla advances from the shell, and its central opening enlarges in propor- tion to the healthy state of the Zoophyte, and the purity and stillness of the water ; its flat, downy, radiated surface gradually diminishes by the widening of the central opening, till only thin margins are left around the orifice and the current is again seen to play briskly from it.” These observations of Dr. Grant I had frequent opportunities of verifying at Tenby, and I can therefore speak with con- fidence as to their accuracy. In addition to the experi- mental touches with a needle, I tried the effect of the application, very delicately, of small drops of nitric and hydrochloric acids, but these strongly stimulating fluids did not cause the slightest contraction of the protruded portion of the sponge. The same distinguished naturalist also states, that “ during the months of March and April, when his obser- vations were made, numerous small yellow ova were seen in the vicinity of the canals, agreeing much in their form, colour, size, and mode of distribution, with those of the Spongia papillaris and S. panicea, which were then nearly in the same stage of advancement.” Dr. Johnston, in his ‘ History of British Sponges,’ p. 125, in his description of the specific characters, says that “ the circular orifices are often filled with a mammillated plug ;” but it is not clear from which of the two varieties he has described of his Halichondria celata he has derived this character. I have myself found such a mammillated plug as he describes, in the surface orifices of the perforated stones at Tenby, but I have satisfied myself that it was no part of the sponge. The true oscular portion of the sponge projected from the orifices of the tubular perforations which it inhabits abound with the proper spicula of the skeleton, and no appearance of mammille can be detected BRITISH SPONGIADA. 215 on any part of the dermal membrane, which is continued without fracture from the extruded portion deep into the body of the sponge, while, on the contrary, the mammil- lated plug spoken of by Dr. Johnston, has not a single speculum embedded in or on its membranes, and is totally detached from the neighbouring sponge tissues. It is very similar in form to the oscular portion of the sponge, but this is the only similarity that exists between them; and it is abundantly evident that this body is simply the remains of one of the lithodomus Annelids which probably excavated the tortuous passages which have subsequently been taken possession of by the sponge. ‘The plug consists of a cir- cular thickened membrane with a central orifice or depres- sion, equal to about one third of its whole diameter. Within this area there is a membrane of a deep blood-red colour. The outer portion of the surrounding membranous ring is thickly studded with mammille, nearly all of which are pear-shaped, the smaller end being the distal one, and the whole present every appearance of being the tentacles of an Annelid in a state of complete retraction. The learned author of the ‘ History of the British Sponges’ has also described two varieties of his Halichondria celata.. The first as “‘ massive and rude.” ‘The second as “ sinuous, the shape dependent on the form of the holes in old oyster shells, which the sponge occupies and fills.” The latter variety is Cliona celata of Grant ; the former now consti- tutes the type of my genus Raphyrus. When Dr. Johnston was writing the history of H. celata, he sent to me for examination, as he states in his work, “‘ some morsels’ of the sponge, requesting my opinion regarding the spicula, camera lucida drawings of which I sent to him, and which he has figured in page 127 in his work. I had not, at that time, seen a complete specimen of Raphyrus, and it is not, therefore, surprising that either Dr. Johnston or I should have mistaken the spicula of one species for those of the other, as their structure and proportions so closely resemble each other as to render it impossible to distinguish between the two by the normal forms of the spicula alone ; the only guide to distinction that a practised eye would find, would 216 A MONOGRAPH OF THE be the occurrence of a few acerate spicula dispersed among those from Raphyrus ; but when we take into consideration the anatomical peculiarities and the external forms of the two sponges, there is not a moment’s hesitation required in distinguishing between them. Mr. Hancock, of Newcastle-on-Tyne, has divided Dr. Johnston’s Halichondria celata into twelve species, nine of which he has designated and described in the ‘ Annals and Magazine of Natural History,’ second series, vol. iii, p. 321, but it does not appear to me that this division into species is natural or justifiable, as they are founded purely on differences in form, without any adequate variations in their structural characters to support such a division. Nearly all these pro- posed new species have the same habit and the same forms of spicula, with only such an amount of variation in size and form as may readily be found in a single field of view beneath the microscope, in any well-known specimen of Halichondria celata of Johnston when mounted in Canada balsam. Since the publication of Mr. Hancock’s paper I have examined a large number of specimens from the North Sea and various other localities, but I have failed entirely in finding one which could not be readily and justly referred to Dr. Johnston’s second variety of the sponge, Cliona celata, Grant. There are four of Mr. Hancock’s species, C. gracilis, Northumbrica, corallinoides, and vastifica, from which he figures small acerate spicula as accompanying the spinulate ones, but he does not say from what part of the sponge he obtained them, nor what proportion they bore to the spi- nulate ones; but as adventitious spicula of various forms are by no means uncommon on the surface of many sponges in their natural state, and as they are frequently firmly cemented on the dermal membrane in the same manner as grains of sand and other extraneous matters are, I must at present doubt their being the normal forms belonging to Dr. Grant’s Cliona celata, and especially as acerate forms of spicula are so exceedingly abundant among the sandy detritus of the sea bottom. There is no British sponge BRITISH SPONGIADA. 217 regarding which there has existed a greater diversity of opinion than the present subject of investigation, and this is, perhaps, in a great measure due to the singularity of its habit, in selecting the perforations of lithodomus annelids, and other marine animals as its habitation, and very few oyster or other shells in which such perforations exist, are tree from this parasitical sponge, but it does not confine itself to the sinuous canals thus formed; if they happen to open into the bases of large parasitic Balani attached to the shell, the whole of the interior of the Balani become coated with the sponge, and in the excavated stones of Tenby it frequently entirely fills the smaller cavities, or completely coats the larger one made by the lithodomus molluscs so abundant in the surfaces of the limestone rocks between high and low water-marks in those districts. In one specimen of the sponge in my possession, dredged by Mr. King at the Scilly Islands, in the summer of 1863, the shell, a single valve of a large Pectunculus, has the outer surface presenting the usual abundance of circular orifices, about a line and a half in diameter, from each of which the sponge is protruded in the usual manner; the inner surface of the shell, which has evidently been the one lying downward, is also furnished with numerous perfora- tions, but as this surface has been protected by its position, the sponge has varied from its usual habit, and has spread itself evenly over the whole interior of the shell, and this surface, about two and a half inches in diameter, was per- fectly smooth and glabrous, and quite destitute of oscula, as might reasonably be expected from their abundance at the outer one; the colour of this extended surface of the gponge was, in its fresh condition, of a dull ochreous yellow, and the only difference that appeared to exist between it and the parts within the substance of the shell, was that of a more abundant secretion of sarcode. ‘his specimen exhibits the largest uninterrupted surface of the sponge I have ever seen; large cavities between the layers of old oyster shells and the interior of shells of dead Balani nearly an inch in height, completely coated by this sponge, are by no means of uncommon occurrence at Tenby, and in the 218 A MONOGRAPH OF THE Guliot caves at Sark. Sections at right angles to the sur- face from the massive part of the sponge on the inner surface of the Pectunculus valve, presented all the characteristic structures that are common to the genus Hymenzacidon, and when compared with portions of the sponge taken from the tortuous canals in the substance of the shell the one could not be distinguished from the other. Some naturalists have promulgated the idea that this species of sponge has the power of excavating the canals and other spaces which it usually occupies. My own inti- mate knowledge of the species has led me to a contrary conclusion. When located in oyster or other shells it usually fills entirely the cavities between the two surfaces, but when the canals excavated in the limestones extend to the depth of two or more inches, it frequently occurs that the sponge terminates at the depth of less than an inch, and the remaining part of the canal is quite empty and clean, without the slightest indication of having been ever occupied by sponge; and in one of these perforated stones from Tenby, which I broke through its centre, although it abounded with the sinuous canals, none of them presented the slightest traces of having ever contained sponge; and occasionally, oyster shells full of perforations may be found in the same condition, one such I have in my possession. These facts militate strongly against the idea that the exca- vations are produced by the sponge; and, in addition to them, we must bear in mind that the dermal membrane is quite smooth, and that there are no mechanical appliances or organs visible by which such a power of attrition could be exerted. Mr. Hancock, of Newcastle, believed that he had discovered the organs by which the sponge effected the perforations, and, with his usual kindness and liberality, he presented me with a specimen of these supposed erosive parts, which I at once recognised as cells secreting carbon- ate of lime, which are found in abundance embedded in the growing membranous tissues of the oyster-shells whence he had obtained his specimens. The perforation of the shells by the agent effecting that operation, would naturally liberate abundant fragments of these membranes, and the BRITISH SPONGIAD. 219 close adherence of such portions to the dermal membrane of the sponge would be very liable to lead to the belief that they were really parts of that animal; but if the sponge be carefully removed from the sinuous cavities of the shell and washed previously to examination, I will venture to say that no such erosive organs will ever be found embedded or organically attached to the dermal membrane of the sponge. I have often seen these cells in fragments of the membranes of the oyster-shells, but have never been able to discover any of them in conjunction with specimens of the sponge taken from the perforated bouldered limestones from the oyster beds of Tenby, or from the perforated surfaces of the limestone rocks of St. Katherine’s Cave, at the same locality. In an oyster-shell from which I have thin sec- tions, the perforations in its substance consist of nearly straight tubes of about the same diameter throughout, and each single one terminates in a round or oval cavity, varying in its diameter from three to eight or nine times the dia- meter of the tube; up some of the tubes the sponge may be seen slowly winning its way, with one or two spicula disposed in a longitudinal direction, while the upper por- tion of the tube and the large terminal cavity is completely empty. In another part of the same specimen there is one of these large, elongo-oval cavities, from which there are four ccecoid canals radiating from it of different lengths, two long and two short; the cavity is entirely filled with the sponge, apparently from a fifth canal connected with the exterior of the shell. Now the condition of the sponge in the four coecoid canals is relatively the same, that is to say, all the parts in immediate proximity to the large cell are filled with the sponge ; the two small ones entirely so, the two long ones only partially so; the shortest of the two long ones, for rather exceeding one third of its length, and the longest for not more than one fourth of its length. This condition of the sponge in relation to the canals and cavities in the shell unmistakably indicate that the cavities and canals were prepared previously, and that the sponge, at the time that life was arrested, was slowly winning its way into them. In the progression of the sponge up one 220 A MONOGRAPH OF THE of these narrow tubes near its base, one or two spicula may be seen, but frequently for a considerable distance from the last spiculum the sponge consists of sarcode only, and in no case were any of Mr. Hancock’s supposed erosive organs to be detected in conjunction with the sponge. The inner surfaces of these cells have a peculiar character ; they are not regularly and evenly bored, but the parietes consist of numerous small concavities, which appear to have been each bored separately, so that the margin of the last one partially obliterates those of its neighbours, and their average diameter is about that of one of the leading canals ; thus it would appear that the same excavating apparatus that applied in a continuously straight direction that formed a tube, was applied in a different manner to enlarge the terminal portion of the cavity by a series of short, lateral borings, and thus to form a large cavity, into which the An- nelid producing it might retire at its leisure, or making it its head-quarters, bore thence other tubes in various direc- tions, to suit its own habits and purposes, and when these were served, and it had either retired from them or died, the excavations were taken possession of by the sponge, just as a Pagurus takes possession of a dead univalve shell. ‘The Annelids found in the borings in the Balani at Sark, and those in the deeply-seated borings of the limestone rocks at Tenby, were distinctly different species ; the former being probably lithophagous, or perhaps more correctly, testophagous in their habits, while the former were litho- domus only. It is well-known to naturalists that the common earth- worm passes the vegetable mould through its intestines, separating the nutrient matter incorporated with it by di- gestion, and ejecting the indigestible matter ; the powerful jaws of the Annelids inhabiting the various species of shells eroding their substance with great facility. ‘The substance thus detached, abounding in animal matter, is most pro- bably passed through their digestive organs, thus affording nutriment, and forming a safe habitation at the same time, and accounting also for the vast number of perforated shells and the comparative rarity of the annelids. BRITISH SPONGIADA. 221 Some naturalists have conceived the idea that the per- forations in the oyster-shells and in limestone rocks so constantly occupied by the sponge, and those also inhabited by lithodomus molluscs, were effected by the secretion, by the animal of carbonic or other acids. The perforation of sound hard wood by such molluscs, and that of a mass of solid Highgate resin, in the British Museum, which still contains the lithodomus shell that excavated it, could never have been effected in the sea or out of it by such agents. On the contrary of both these views, I have in my collection several specimens of large Balani, which I took from the sides of the rocks forming the Guliot Caves in Sark, which are perforated, in the usual manner, with numerous sinuous canals, which I found filled with the living Annelids, the dried remains of which still remain in them, and without the slightest indication of the presence of 4. celata, and I have also found living Annelids in the deeply-seated portions of the perforations in the limestone boulders of Tenby, beyond the range of the sponge; so that I think it may be reasonably concluded, that the sponge occupies the canals and cavities in shells and stones that have been excavated by other animals, and that they have no power to excavate such residences themselves. Such speculative views regarding the habits and powers of marine animals by inland and imaginative naturalists are very apt to mislead the young student. A little close ob- servation and accurate description at the proper localities, is infinitely more valuable than a laborious closet treatise on such subjects. Dr. Grant, I believe, gave no generic description of Chona, and, in his account of it, stated that it was poly- piferous. Dr. Johnston, after careful examination, not con- sidering it to be a Zoophyte, referred it to its proper place in the system of arrangement of the sponges that was then received, as a Halichondria, and subsequently in the division of that genus into numerous others, I have referred it to the extensive genus Hymeniacidon. There can be no reason- able doubt that had not Dr. Grant been misled by ac- cidental circumstances, and thereby been induced to believe 222 A MONOGRAPH OF THE it to be a Zoophyte, he would have designated it as a Spongia. 36. HyMENIACIDON GELATINOSA, Bowerbank. Sponge. Coating, thin, gelatinoid. Surface smooth and even. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane aspiculous. Skeleton, consisting of a few long and slender spinulate spicula, usually dispersed on a basal membrane, rarely loosely fas- ciculated. Colour.—In spirit, dull-green. Habitat.—Dourie Voe, Shetland, Rev. A. M. Norman. Examined.—From the spirit. There is very little can be said about this species. It is one of the simplest spongeous bodies I have yet seen. It consists of a slightly oval patch, about eight lines in length by six in width, and not exceeding half a line in thickness, on a thin fragment of sand-stone shale, slightly exceeding the sponge in size. In its present condition it closely re- sembles a drop of glue spread out on the small fragment of stone. When viewed by the aid of a lens of an inch focus the surface appears smooth and even, and the oscula, although they are all closed, are apparent, as the distal terminations of the excurrent orifices are distinctly seen through the transparent dermal membrane, which is also slightly depressed over the orifices. When a small portion of the sponge was immersed in distilled water innumerable minute globular vesicles were liberated from the sarcode, which appears to consist nearly entirely of these molecules. Small pieces, of the entire thickness of the sponge, mounted in Canada balsam, exhibited the spicula 2x situ, but they were so few in number that they were as frequently isolated as they were crossing or touching each other ; they were all long and slender, but very variable in their proportions; a few were congregated in two loose fasciculi, all their bases BRITISH SPONGIADA. 223 being at one end of them and all their apices at the other, and they were also not more than about half the length of the dispersed ones. 37. HYMENIACIDON PAUPERTAS, Bowerbank. Sponge. Sessile, coating. Surface very irregular, strongly hispid. Oscula inconspicuous, simple, dispersed, minute. Pores inconspicuous. Dermal membrane pellucid, furnished abundantly with sub-fusiformi cylindrical spicula, dispersed or loosely fasciculated. Skeleton ; spicula attenuato-clavate, basally spined, large and long. External defensive spicula, same as those of the skeleton. Internal defensive spicula, attenuato-clavate, entirely spied. Retentive spicula, expando-tridentate equi-anchorate, very stout and strong. Interstitial membranes, tension spicula, same as those of the dermal membrane. Colour.— Dark amber. Habitat—Shetland, parasitical on Zoophytes, Rev. A. M. Norman. Examined.—In the dried state. The appearance presented by this sponge is very poor and uninviting. It coats the stem of a Zoophyte for about two inches of its length so thinly and irregularly, as at first sight to induce the idea that it is in a very early and im- mature stage of growth, instead of being in a completely adult state. The surface is extremely cavernous and uneven, and the hispidation, which is produced by the large external defensive spicula, is very prominent ; the spicula projecting from all parts of the surface and into the cavernous depres- sions for nearly the whole of their length. The dermal membrane is thickly covered with either dispersed or fas- ciculated sub-fusiformi-cylindrical spicula ; the fasciculi are loosely gathered together into wide flat bundles, which have no regularity in their mode of disposition. In the 224 A MONOGRAPH OF THE interstitial membranes they appeared to be more frequently dispersed than fasciculated. The form of the skeleton spi- cula very closely resembles those of Hymeniacidon clavigera, but their bulbous bases do not appear to be exaxial, as in that species. They are long and powerful, and the spination does not extend beyond the base more than about a sixth or a seventh of their whole length. The internal defensive spicula are of the same form as the skeleton ones, but they are entirely but minutely spined, and are not above one fourth or one third the length of a full-sized skeleton spi- culum. The expando-tridentate equi-anchorate spicula of the sarcode are very characteristic of the species ; the teeth are strongly produced, and the lateral ones widely spread ; the shaft is very stout, and frequently curved to the full extent of a semicircle. From the similarity of the skeleton spicula of this sponge to those of H. clavigera, the two sponges might be readily mistaken for each other, if it were not for the strikingly characteristic forms of the anchorate spicula, which do not occur in H. clavigera. 38. Hymeniacipon Dusarpinu, Bowerbank. Hatisarca Dusarprtl, Johnston. Sponge. Coating, thin. Surface smooth and even, gela- tinoid. Oscula and pores inconspicuous. Dermal membrane abundantly covered internally with dis- persed skeleton spicula. Spicula of skeleton cylindrical, long, very slender, and often flexuous. Internal de- fensive spicula attenuato-acuate, basally and medially spinous, large and stout; spines conical, large, and very numerous at the base. Colour.—Alive, ochreous yellow to deep amber colour. Habitat—Berwick Bay, Dr. Johnston; Strangford Lough, Dr. Dickie; Scarborough, Mr. Bean and J. S. Bowerbank. BRITISH SPONGIADA. 225 With the assistance of my friend, Mr. Bean, I found this sponge on the underside of small slabs of yellow oolitic sandstone between high- and low-water marks about two miles north of Scarborough; when fresh from the sea, it had the appearance of a thin layer of dark-amber coloured gelatine, and no oscula were visible. In the fresh state, it was scarcely a line in thickness, and, in its dried condition, it is not thicker than a sheet of writing-paper. Professor Dickie’s specimen from Strangford Lough, on a shell of Pecten opercularis, is rather thicker, and is darker coloured than the Scarborough one. ‘This sponge was designated Halisarca, by Dujardin, from his believing it to be destitute of spicula; and my friend, Dr. Johnston, failed to detect them in the specimens he found in Berwick Bay. I am not astonished that they eluded the observation of these eminent naturalists, as the spicula are very slender, and so completely embedded in the sarcode as to render them very difficult of detection when the sponge is in its natural condition, and it is only when a portion of it is immersed in Canada balsam, and with a power of about three hundred linear, that they are rendered distinctly visible. ‘the principal portion of the sponge consists of the der- mal membrane, which is covered internally with irregularly dispersed skeleton spicula, amidst which solitary specimens of the defensive spicula may be observed lying in various directions. The interstitial membranes are few, very short, and crowded with spicula. ‘lhe forms of the spicula are very characteristic of the species, and the defensive ones especially so. The entire structure of the sponge is in perfect accord- ance with the other known species of thin coating sponges of my genus Hymeniacidon, amongst which I have there- fore thought it advisable to place it. The genus Halisarca was founded. in a misapprehension of the structure of the animal. Had Dujardin been aware of the existence in its structure of membranes and spicula, such as are now shown to be abundant, he certainly would not have made a sepa- rate genus of it, but would have placed it among its 15 226 A MONOGRAPH OF THE congeners; and, with English naturalists of that period, it would have been arranged among the species of Halichon- dria, and on the subsequent division of the latter, it naturally takes its place as a Hymeniacidon. Well founded genera should always be maintained if possible, but I do not see the necessity for scrupulously maintaiming those which are so only in name, and are not so in essential character. 39. Hymenracipon Buckuanni, Bowerbank. Sponge. Massive, sessile; surface minutely hispid, even. Oscula simple, dispersed. Pores inconspicuous. Dermis stout, minutely maculated; furnished abun- dantly with minute, entirely spined, cylindrical spicula ; spines large, and obtusely terminated. Skeleton spi- cula; spiculated triradiate and attenuato-biangulated, large and stout. ‘Tension spicula tricurvate, few in number. Sarcode; dark purple, semi-opaque, abound- ing with minute, entirely spined, cylindrical spicula, like those of the dermis. Colour—Alive, external dark purple; internal, light brown. Hlabitat.—Torquay, Dr. Battersby ; Guernsey, Mrs. Buckland. This remarkable sponge, in its dried state, very closely resembles in firmness and colour a piece of dried boiled bullock’s liver. A specimen with which I have been favoured by the late Mrs. Buckland, who obtained it at Guernsey, at the extreme low-water mark, was two inches in length, and one in breadth and thickness. When a thin slice from the surface is mounted in Canada balsam, the dermis is seen to abound in small, ill-defined dark macule, and minute, entirely spined, cylindrical spicula. If the section be mounted for examination in water, the first of these characters is but indistinctly visible, while the spicula are completely invisible, in consequence of the density and BRITISH SPONGIADA. 227 opacity of the sarcode ; and this observation applies equally well to the interstitial structures of the interior of the sponge. ‘The minute spicula rarely exceed ,ith of an inch in length, and require a linear power of about 600 to render them distinctly visible. They are profusely spinous, and the spines towards the middle of the spiculum are frequently as long as the greatest diameter of the shaft of the spiculum on which they are based. The spicula of the skeleton of this sponge are very re- markable. The spiculated triradiate ones have the three radii applied evenly to the under surface of the dermal membrane, while the shaft or spiculate ray is projected amid the tissues beneath, at right angles to the surface of the sponge. In the biangulated spicula the two points of one angle are applied to the inner surface of the dermal membrane, and the opposite pair of points are immersed in the body of the sponge; and this appears to be the in- variable position of these spicula at the surface of the sponge; but in the interior I] could not detect any such definite arrangement, but the spicula appear to be dis- persed on the tissues at such distances from each other as just to allow of their apices touching, or slightly crossing each other, and the two forms appear to be indiscriminately mixed together. Throughout the whole of the tissues we find minute entirely spined cylindrical spicula, like those of the dermis, dispersed in great abundance. The tricurvate tension spicula of the interstitial mem- branes are few in number and very slender; the central curve is distinctly produced, while the terminal ones are but very slightly so. The two forms of skeleton spicula in this species are very similar in degree of size and stoutness, and in some positions they are not readily to be distinguished from each other, but they may always be determined by the fact, that in the spiculated triradiate form the central canals, at their junc- tion in the middle of the spiculum, form three angles of each about 120°, and three others, which are right angles ; while those of the biangulated spiculum form four right angles only at their crossing at the centre of the spiculum. 228 A MONOGRAPH OF THE The central canals, and the concentric layers of silex in the radii, are remarkably distinctly exhibited. Tam indebted to my friend, Dr. Battersby, for the first intimation I received of the existence of this curious and interesting species on our own coasts; he found it at Torquay, at extreme low-water mark, on the rocks of Abbey Bay, adjoining Torquay. Preserved in salt and water, it is almost as solid as a piece of boiled bullock’s liver. This sponge varies so widely from the ordinary structures of Hymeniacidon, that I doubt much whether it should not have been made the type of a new genus. Hauicnonpeta, Meming. Section * Skeleton spicula, acerate. 1. Halichondria panicea, Johnston. — glabra, Bowerbank. — angulata, Bowerbank. — caduca, Bowerbank. _ — tnconspicua, Bowerbank. incerta, Bowerbank. — coalita, Johnston. ‘ — distorta, Bowerbank. IH sre go 19 | Section * * Skeleton spicula, acuate. Sub-section A. Skeleton spicula, smooth. 9. Halichondria corrugata, Bowerbauk. 10. — Thompsoni, Bowerbank. LI, — Sores, Bowerbank. 12. — simplex, Bowerbank. 13. — subdola, Bowerbank, BRITISH SPONGIADA. 229 Sub-section B, Skeleton spicula, spinous. 14. Halichondria incrustans, Johnston. 15. — candida, Bowerbank. 16. — wrregularis, Bowerbank. 17. — Dickiei, Bowerbank. 18. — Pattersoni, Bowerbank. 19; — pulchella, Bowerbank. 20. — Ingaili, Bowerbank. 2). — scandens, Bowerbank. 22. — Batei, Bowerbank. 23. — granulata, Bowerbank. 24. — Hyndmani, Bowerbank. 25. — Nigricans, Bowerbank. 26. — albula, Bowerbank. Szorion * * * Skeleton spicula, spinulate. 27. Halichondria farinaria, Bowerbank. 28. — énornatus, Bowerbank. 1. Hauicnonpria panicra, Johnston. HALIcHONDRIA SEVOSA, Johnston. Sponge. Coating massive or fistulous, very variable in form, sessile; surface smooth. Oscula simple or slightly elevated ; dispersed on the surface, or collected in large or small fistulous cloace. Pores incon- spicuous, numerous. Dermal membrane simple, pel- lucid, abundantly spiculous; spicula either arranged in rete, or irregularly dispersed. Skeleton: Spicula acerate or sub-fusiformi acerate. Sarcode abundant. Colour —From light ash to yellow, orange, or green of various tints, 230 A MONOGRAPH OF THE Locality—All parts of the Coasts of Great Britain. Examined.—Alive. The shape of this sponge varies exceedingly. In its young condition it forms a thin smooth coating, on stones or fuci, frequently not exceeding three or four lines in thickness, or it envelops the stems of small Fuci or Zoophytes, and ultimately becomes free rolling masses of every variety of shape; or if it remains adherent to its original attach- ment, it becomes thick and massive, or it is projected in the form of one or more thick, elevated ridges, and it is then the cock’s comb sponge of Ellis. In its greatest degree of development it frequently assumes a fistulous form. In the living state the surface is smooth and even, but in the dried condition it presents a structural character by which, when once familiar to the eye, the species may be almost always easily detected ; and that is a beautifully reticulated appear- ance of the surface when viewed by an inch lens. This character is not inherent in the dermal membrane, but is simply an impress of the reticulated skeleton of the sponge immediately beneath its surface, and is therefore a constant character, and one the like of which I do not remember to have seen in any other British species of sponge. The oscula when on the surface are large, irregularly dis- persed, sometimes perfectly simple orifices, at others thinly margined or slightly elevated, and mammeeform ; but when collected in fistulz, they are always simple. The fistule vary much in size and form. In one little specimen col- lected in the Menai Straits near Bangor, the whole sponge had assumed the form of five or six fistulae, each about three lines in diameter, and about a quarter of an inch in height, thus very closely simulating a small specimen of Polymastia mammillaris. Yn specimens from Tenby the fistulee are projected about an inch and half in height, and exceed half an inch in diameter ; from Fowey in Cornwall I have them from my indefatigable friend Mr. Peach, exceeding six inches in length and three quarters of an inch in diameter; and in a very fine specimen from Belfast Lough, sent to me by my late friend Mr. Wm. Thompson, BRITISH SPONGIADA. 231 the mass, nine inches by six at the base, is covered by very large fistulee, some of which are six inches in height, while others not exceeding three inches in length have an external diameter of more than one and a quarter inches. In all these cases the mner surfaces of the fistulae are abounding with simple oscula, while on the general surface of the sponge there is scarcely one to be seen. The pores are frequently beautifully displayed in dried specimens of this sponge. Figure 303, Plate XIX, vol. i, represents a portion of such a specimen. ‘The variations of their character on the surface of the same sponge is often extremely great. In one spot it will be beautifully reticu- lated, and the area of every one of the meshes will be occupied by several pores, while within the quarter of an inch of the reticulated part the surface will be entirely devoid of either reticulations or pores, and in this case the dermal membrane is frequently furnished with a thickly matted lining of spicula without the slightest vestige of arrangement. Dr. Johnston, in his ‘ History of the British Sponges,’ page 147, has described a species found on the shore of the Isle of Man by the late Professor Edward Forbes, under the name of Halichondria sevosa. I have been unable to detect any organic difference between the type specimen now in the British Museum and the common specimens of Halichondria panicea; and a careful in- spection of the type specimen leads me to believe that the sponge was not erect, but that it had grown coating a Fucus, or some other such substance. Upon no part of the margin is there the slightest indication of a base or attach- ment. The “Fatty” character described by Dr. Johnston exists only in its appearance to the eye, the texture beneath the microscope is exactly that of a young thin coating specimen of H. panicea, and the surface in its present state is quite smooth. There can be no reasonable doubt that the “ Sponge-like crum of bread” described by Ellis in his ‘ History of Corallines,’ No. 2, page 80, Plate XVI, d, and that desig- nated H. panicea by Dr. Johnston in his ‘History of British Sponges’ are identical; but the author of the latter 232 A MONOGRAPH OF THE work is in error in considering the sponge described by Dr. Grant in the ‘Edinburgh Phil. Journ.,’ XIV, p. 114, as the same species as Ellis’s sponge. Dr. Grant has kindly furnished me with specimens of the sponge that formed the subject of his paper, and in neither external nor internal characters does it agree with Ellis’s species. I am therefore induced to believe that my friend Dr. Johnston could not have seen Dr. Grant’s specimens when he wrote his ‘ His- tory of the British Sponges.’ Ellis’s sponge has certainly a prior claim to the name of panicea, and the species so ably described by Dr. Grant must retain the naine of /alichon- dria incrustans, under which designation it is described by Dr. Johnston, ‘ History of British Sponges,’ page 122. This species is quite as variable in colour as it is in form. When littoral it is most frequently yellow, orange or green; but when from five or ten fathoms in depth, it is usually ash gray or cream coloured. I cannot do better than to refer my readers to Dr. Jobnston’s excellent history of this species in his work on ‘British Sponges,’ for the general account of this very protean sponge. The large number of species into which its different forms have been divided by various authors strongly illustrates the inutility of external form as a prin- cipal specific character in the description of the species of the Spongiade. 2. Hanicnonpria GLABRA, Bowerbank. Sponge. Coating thin. Surface smooth and glabrous. Oscula simple, very small, im dispersed groups of three to five or six in number. Pores inconspicuous. Dermal membrane translucent, furnished with an irregular network of spicula, rete frequently multi- spiculous ; spicula same form and size as those of the skeleton. -Skeleton. Spicula sub-fusiformi-acerate, long and slender. Colour.—When dried, pale yellow. BRITISH SPONGIADE. 233 Locality.—Scarborough, Mr. Bean. Examined—When dry. This sponge coats the greater part of the surface of a piece of sandstone nearly four inches square, but does not exceed the eighth of an inch in thickness at any part, and in its dry condition it might readily be mistaken for a coating specimen of Halichondria panicea when only super- ficially examined ; but the peculiar glabrous appearance of the surface readily distinguishes it from that species, and especially if a lens be used to examine it. The oscula are few in number and small, and the groups are widely dis- persed. The spicula of the skeleton are half as long again as those of H. panicea, more slender and disposed to be flexuous, and from the condition of these organs the general texture of the interior of the sponge is coarser and more open. ‘The dermal membrane is somewhat thicker, and the number of the pores very much fewer than in Z. panicea, and there does not appear in the specimen ex- amined the slightest tendency to elevation of the oscula. 3. HaLicHoNDRIA ANGULATA, Bowerbank. Sponge. Massive, sessile. Surface smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane translucent, furnished with a unispiculous network ; spicula acerate, same size as those of the skeleton ; and also with small and very slender acerate, and sub-angulated tricurvate acerate tension spicula, rather numerous. Skeleton. Rete rather irregular, occasionally multi-spiculous ; spicula acerate. ‘I'en- sion spicula, acerate, small and slender, and sub- angulated tricurvate acerate spicula. Colour.—Dried, light gray. Habitat —Guernsey, Rev. A. M. Norman. Examined.—In the dried state. 234 A MONOGRAPH OF THE The specimen in course of description is but a fragment of the perfect sponge. It is one inch in length, half an inch broad, and four lines in thickness, and in its present state it is exceedingly friable. The dermal membrane presents excellent specific characters ; the unispiculous net- work is irregular in its area, but uniform in its general character; the spicula forming it are not united at their apices, but they cross each other at various angles, forming triangular and quadrangular spaces, the sides of which are less in length than the spicula bounding them. When the sarcode is well preserved, the minute acerate, and sub- angulated tricurvate acerate spicula are abundantly dis- persed, the latter being much more numerous than the former. The sub-angulated spicula are remarkable in their character, the central curve in the greater portion of them is so abrupt as to frequently cause the spiculum to assume the form of a right angle, while the terminal curves are but very slightly produced ; but this extreme angula- tion, although it obtains to a considerable extent, is not universally prevalent, and others may be found exhibiting the usual variations in form and curvature that occur among this form of spicula. The same descriptions of tension spicula occur on the interstitial membranes, but apparently not to so great an extent as on the dermal one. The specimen described is the only one of the species T have seen. It was sent to me among the sponges dredged off Guernsey by the Rev. A. M. Norman. I do not recol- lect to have seen tricurvate spicula in any other sponge of the first section of Halichondria. 4. Hanicnonpria capuca, Bowerbank. Sponge. Massive, sessile, surface rugged. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane spiculous, spicula same as those of the skeleton, dis- persed, numerous, and a few acerate, very slender. Skeleton diffuse, and very irregular ; spicula sub- fusiformi acerate, rather stout and long, rarely acuate. BRITISH SPONGIADA. 235 Interstitial membranes thin and translucent; spicula same as those of dermal membrane, but less in number. Colour.—Dried, light gray. Habitat.—Tenby, Mrs. Brett. Guernsey, Rev. A. M. Norman. Scarborough, Mr. Bean. Examined.—lIn the dried state. The structure of this sponge is very irregular. It is composed of loosely aggregated fascicula of spicula which form a very irregular and disconnected network, and the spicula of the bundles appear to have been but very slightly cemented together with keratose structure; other spicula of the same form and size are irregularly disposed amid the network. ‘The interstitial membranes are very thin and pellucid, and when mounted in Canada balsam are scarcely visible. ‘The dermal membrane in adult specimens is crowded with spicula of the same size and form as those of the skeleton, with, oceasionally, others of the same form, but small and slender. In the specimen found by Mrs. Brett at Tenby, there were more of the slender spicula than in the larger and probably older specimens obtained by Mr. Norman, at Guernsey, in which they were rather rare. The type specimen in its present form is eight lines in length by six in breadth, and the same in height, but it is evidently a portion only of the original mass. Mrs. Brett, to whom I am indebted for my first acquaintance with this species, found it between high- and low-water marks on the northern side of St. Katherine’s Rock, at Tenby. ‘The colour when alive, I am informed, was the same as when dried, light gray approaching closely to white. I have subsequently examined a second specimen col- lected by my late friend Mr. Ingpen, and now in the pos- session of the Rev. Alfred M. Norman. It agrees with the type specimen in every respect excepting in its form, which is irregular. Massive towards the middle portion with three short projecting portions, and is evidently modified in 236 A MONOGRAPH OF THE shape by the Fucus on which it is based and which it par- tially envelops. A third specimen in the cabinet of Mr. Bean of Scarborough, has enveloped several small stems of a Zoophyte, and has thus assumed very much the size and branched form of a small specimen of Diéctyocylindrus rugosus; six specimens dredged by the Rev. A. M. Norman, at Guernsey, ranged from six lines in length to an inch and a half. They were all parasitical on small Fuci, and were irregularly massive inform. It therefore appears that the species does not attain a great size. 5. HaricHonpria inconspicua, Bowerbank. Sponge. Massive, sessile; surface rugose. Oscula simple, large. Pores inconspicuous, and not very numerous. Dermal membrane pellucid ; spicula same as those of the skeleton, numerous, usually dispersed, sometimes fasciculated. Skeleton spicula acerate, stout, and rather short. Tension spicula of the interstitial membranes, acerate, slender. Colour.—Dried, light gray. Habitat—Tenby, Mrs. Brett. Examined.—In the dried state. I have seen but one specimen of this sponge. It isa small mass nine lines in length, six in breadth and the same in height; the surface is nearly even, but somewhat rugged. It has one large osculum which is simple and irregular in form, its greatest diameter rather exceeded two lines ; there were also two or three smaller ones, less than a line in diameter. ‘The pores are visible by the aid of an inch lens. The greater part of the dermal spicula are irregularly dispersed, but occasionally they are collected into elongated fasciculi, simulating the appearance of frag- ments of primary lines of an Isodictya; but no such fasci- culi appear in the mass of the sponge when a section at right angles to its surface is examined, BRITISH SPONGIADA. 237 The acerate spicula of the skeleton are short in com- parison with many other species having the same form ; the tension spicula of the interstitial membranes are very little inferior in length to the skeleton spicula, but much more slender. The only species of Halichondria with which this sponge is likely to be confounded is HZ. caduca, but the difference in the length of their skeleton spicula readily serves to distinguish them, those of H. inconspicua being little more than half the length of those of ZH. caduca. 1 am indebted to my kind friend Mrs. Brett, of Tenby, for this new species. It was gathered between high- and low-water marks on the northern side of St. Katherine’s Rock, at Tenby, and I am informed was nearly of the same colour when alive as it is in the dried state, and that while drying it emitted a smell similar to heated vinegar. 6. HaxticnonpRia IncERTA, Bowerbank. Sponge. Sessile, coating. Surface rough and uneven. Oscula simple, dispersed, numerous. Pores incon- spicuous. Dermal membrane abundantly spiculous ; spicula acerate, rather slender, dispersed, closely felted together. Skeleton irregular, rete slender, very in- distinct, spicula acerate, as long, but stouter than those of the dermal membrane. Interstitial mem- branes, tension spicula very abundant, same as those of the dermal membranes, irregularly dispersed. Colour.—Dried, sulphur yellow. Habitat—Guernsey, Rev. A. M. Norman. Ewamined.—In the dried state. This sponge entirely coats a Balanus about an inch in height, but does not attain a greater thickness than a line, im any part. The dermal membrane is remarkably crowded with spicula, they cross each other in every possible direc- tion, and present the appearance of having been felted together, and this crowding of the spicula appears to obtain 238 A MONOGRAPH OF THE in all parts alike of the dermal surface. The reticulation of the skeleton contain but very few spicula, and it is very difficult to distinguish its true characters in consequence of the extreme abundance of the tension spicula, and it is only in recently produced portions of the skeleton that its reti- cular skeleton can be satisfactorily observed. These pecu- liarities in its structure cause it very closely to simulate the organization of a Hymeniacidon, but the short proportions of the spicula, and the close texture of the internal cavities of the sponge, greatly induce an observer to doubt its belonging to that genus, and a more careful examination will rarely fail to identify portions of the reticulations of the skeleton. ‘The only species in the same division of Halichondria with which this sponge is liable to be con- founded is H. inconspicua, but the difference in the length and proportions of their spicula will, on a comparison, always distinguish them. Those of H. inconspicua is in length as five to six to those of H. incerta, and at the same time, although longer in the latter, they are less in diameter than those of the former. 7. HaticHonpria coats, Johnston. Sponela coaLita, Grant. Sponge. Sessile, irregularly latticed by rounded or com- pressed inosculating branches. Surface smooth. Oscula simple, dispersed, few in number. Pores inconspicuous. Dermal membrane pellucid, abun- dantly spiculous; spicula subfusiformi acerate, variable in length and diameter. Skeleton. Interstitial spaces rather uniform. Spicula same as those of the dermal membrane, very variable in length and diameter. Colour.—Light gray. Hatbitat— Coast of Devon, Montagu. Frith of Forth, and Coast of Sheppey, Dr. Grant. Examined.—In the dried state. BRITISH SPONGIADA. 239 I am indebted to Dr. Grant for a fine specimen of this sponge which he found on the shingle opposite Mile-town, Sheerness, Sheppey. His description of the external cha- racters of the species is so good that I cannot do better than quote it for the information of the reader. ‘‘ When coalita is young, its branches are long and slender; they shoot in all directions to seek for points of attachment and adhere to, or envelop every thing they meet with, living or dead, animal, vegetable, or mineral; wherever the branches cross or touch each other, they form a perfect union; sometimes the animal spreads as a layer over an oyster shell, or covers a rock like a convoluted bush, or hke the root of a Fucus, or forms a cement connecting into a mass all manner of shells, stones, or broken glass ; some- times it forms an irregular mass, with a perfectly smooth surface, without any point of attachment, rolling to and fro at the mercy of the waves. As it advances in life, its colour assumes a darker shade, with a tinge of brown; it becomes less smooth on the surface and loses its trans- parency.” The specimen represented in Plate XII, fig. 1, in Dr. Johnston’s ‘ History of British Sponges,’ and that presented to me by Dr. Grant, very closely resemble each other, so that no doubt can remain of the identity of the species. The skeleton structure of this sponge is more uniform than that of H. panicea ; the interspaces are very much more equalised, although in no degree symmetrical; and as a type of the acerate division of Halichondria, it is certainly better than H. panicea. The specimen marked Spongia coalita in Montagu’s collection of sponges in the possession of Dr. Grant is certainly Hal. simulans of Dr. Johnston, and not Spongia coalita of older authors as Montagu believed. I doubt very much that the species designated Halichondria coalita, by Johnston, is the same as that figured by Miiller in_his ‘Zoologia Danich,’ t. cxx, as Sponyia coalita, and presumed by him to be the same as Ellis’s Spongia ramosa Brittanica, which there is no question is the species designated by Johnston Halickondria oculata ; but Esper’s Spongia sub- 240 A MONOGRAPH OF THE erosa, represented in his Sponge Tables XLT, is undoubtedly the same species as that designated Spongia coalita by Dr. Grant, and Halichondria coalita by Jolnston. 8, Hazicnonpria Distorta, Bowerbank. Sponge. Branching, branches compressed, terminations hemispherical. Parasitic. Surface smooth. Oscula simple, small, numerous, dispersed. Pores incon- spicuous, numerous. Dermal membrane _pellucid, abundantlyspiculous, reticular; spicula acerate, slender, rather short. Skeleton spicula acerate and acuate, stout, variable in proportions ; interstitial membranes, tension spicula, acuate and acerate, long, straight, and somewhat slender. Colour.—When dried, light gray. Habitat—Near Torbay, Mrs. Griffith. River Orwell, Dr. W. B. Clarke. Ezxamined—In the dried state. I have seen but two specimens of this sponge ; the first was procured by Mrs. Griffith from one of the Brixham trawlers, the exact locality cannot, therefore, be given; the second one was presented to me by Dr. W. B. Clarke, of Ipswich, who dredged it in the River Orwell. Mrs. Griffith’s sponge consists of a fan-shaped series of short distorted compressed branches which occasionally anasto- mose, and are nearly all in the same plane. The basal portion of the branches are solid and cork-hke in texture; the denseness decreases gradually in proportion as we approach the termination of the axis where it is scarcely perceptible. This character does not exist to so great a degree in Dr. Clarke’s specimen. ‘The height of the first specimen is six inches, and its greatest width seven inches. Dr. Clarke’s sponge is about the same height, but not so broad ; in other respects it is very similar BRITISH SPONGIADA. 241 to the first one. The base of Mrs. Griffith’s sponge has been destroyed, but that of Dr. Clarke’s is smooth and rounded, and has several fragments of Sertularia projecting from it, and these Zoophytes are continued through its whole length, and are seen projecting from the terminations of several of its branches. A small Buccinum is partially imbedded in the basal portion of the sponge, but its true habit appears to be parasitic, surrounding Zoophytes or other branching bodies. Both specimens are inelegant and distorted in form. The diameter of some of the largest of the oscula is about the tenth part of an inch, but the greater number are very much smaller in size. The pores are not visible without the aid of an inch lens; they are very numerous, and are equally dispersed over the surface of the sponge. The dermal membrane is in fine preservation in Dr. Clarke’s specimen. It is furnished with a network formed of bundles of spicula which are frequently continuous in curved lines over the breadth of five or six of the areas; they cross each other at various angles, and, as several of these elongate bundles are frequently coincident in their direction, there is an approach to a symmetrical arrange- ment in the network that is very remarkable and charac- teristic. The acerate spicula of the dermal network are slender and short in comparison with those of the other parts of the sponge. The acerate spicula of the skeleton are short and stout, while the acuate ones are larger and more slender in their proportions; the two forms are mingled indiscriminately in the fasciculi of the skeleton, but the acerate one is the most numerous. The tension spicula of the interstitial membranes are of the same form as those of the skeleton, but are more elongate and slender in their proportions ; they are not numerous, and the acuate form prevails in number. 16 242 A MONOGRAPH OF THE 9. HaLicHonpria corrucata, Bowerbank. Sponge. Sessile, coating or parasitical. Surface smooth, but uneven and corrugated. Oscula simple, dis- persed, small. Pores inconspicuous. Dermal mem- brane spiculous, strongly reticulated; spicula fusiformi- acuate, stout, same size as those of the skeleton. Skeleton. Reticulation stout, multispiculous ; spicula fusiformi-acuate, stout, and rather short. Tension spicula same as those of the skeleton, few in number. Retentive spicula simple and contort bihamate, large, few in number. Colour.—Alive, blood-red ; dried, light red. Habitat.—Diamond Ground, off Hastings, J. S.. Bower- bank. Douglass, Isle of Man, Mr. Joshua Alder. Island of Herm, near Guernsey, Rev. A. M. Norman. Examined.— Alive. I am indebted to Mr. Alder, of Newcastle-upon-Tyne, for the first specimen I had seen of this species. It is ovoid in form, the apex being the largest end. It is an inch in height, and about half an inch in diameter. Mr. Alder described the colour as red, when alive. Subsequently I obtained, at Hastings, two living specimens from the Diamond Trawling Ground. One of these enveloped a branching Zoophyte for about the length of three inches, and had a diameter of about half an inch. The surface of this specimen was uneven, and much corrugated. The other partially covered a small dead specimen of Desmacidon egagrophila, intermixed with portions of a Zoophyte, and following the plane of the mass on which it was based ; it assumed the form of an irregularly-shaped fan, an inch and a quarter in height, and two and a quarter inches in breadth, the greatest thickness not exceeding a quarter of an inch. When alive, both surfaces were smooth, and pre- sented the appearance of a deep blood-red flesh-like sub- BRITISH SPONGIADZ. 243 stance, and when dried they exhibited a very slight amount of corrugation. In the latter condition, the surface is strongly reticulated, very closely resembling that of Hali- chondria panicea ; and in this state, the pores are distinctly apparent with the aid of a two inch lens. With a micro- scopical power of about 100 linear, the dermal membrane is a very Interesting object, with its beautifully reticulated structure, abounding in its areas with the open inhalent pores of the sponge. ‘The oscula are small. I could not detect them readily in the living specimens; but, in the dried condition, they are apparent to the unassisted eye. The strongly reticulated multispiculous skeleton, combined with peculiarities of the dermal membrane, readily"distin- guish this species from others nearly resembling it in ex- ternal form and colour. 10. Hantcnonpria Tuompsoni, Bowerbank. Sponge. Coating, surface even. Oscula few, large, slightly elevated. Pores conspicuous. Dermal membrane, simple, pellucid, sparingly furnished with bidentate equi-anchorate retentive spicula. Skeleton. Rete dif- fusive;. spicula sub-fusiformi-acuate, sub-flexuous. Interstitial membranes. Tension spicula acuate, long, and slender. Retentive spicula bidentate equi-ancho- rate. Colour.—When dry, brown. Locality.— Belfast, or Larne Lough. Ezxamined.—In the dry state. The texture of this sponge, in the dried state, is firm and rigid, and the rete very open and diffusive, the sides of the network being frequently longer than the skeleton spicula, and the interstitial membranes often assuming much of the appearance of those of a Hymeniacidon. The spicula of the skeleton when not fully developed are usually purely acuate, but in their completely developed state they are 244 A MONOGRAPH OF THE decidedly sub-fusiform ; and there is a general tendency to flexuousness. ‘The tension spicula of the interstitial mem- branes are acuate, and very much more slender and flexu- ous than those of the skeleton. ‘The retentive spicula are minute, they require a linear power of about 600 to define their proportions well; the dente are long, and their apices are slightly exflected, and they mostly appear to be attached firmly to the membranes by the middle of the back of the shaft of the spiculum. The specimen described covers the surface of one valve of Pecten opercularis for about a quarter of an inch in thickness ; it formed part of the collection of the late Mr. William Thompson, of Belfast ; it is now in the museum of that town, and I have dedicated the species to him, in commemoration of the valuable services he has rendered to science by his ardent pursuit of natural history, and the liberality with which he always placed both his specimens and his knowledge at the service of his brother natu- ralists. 11. Haticnuonpria ForciPis, Bowerbank. Sponge. Massive, sessile. Surface uneven, smooth. Os- cula simple, dispersed, rather small. Pores incon- spicuous. Dermal membrane spiculous. Tension spicula sub-clavated cylindrical, dispersed or congre- gated in loose fasciculi ; retentive spiculi bi- and tri- dentate equi-anchorate, large and stout, and bidentate equi-anchorate spicula very minute, also bihamate, simple and contort, very minute and numerous. Skeleton. Rete multispiculous. Spicula acuate, stout, and rather long. Interstitial membranes. abundantly and variously spiculous. Tension spicula sub-clavated cylindrical, dispersed or congregated in loose fasciculi, also forcepiform spicula entirely incipiently spined, shafts of equal or unequal lengths, dispersed or congre- gated in fasciculi; retentive spicula bi- and tridentate equi-anchorate, large and stout, also bidentate equi- BRITISH SPONGIADA. 245 anchorate, very minute, dispersed; and bihamate, simple and contort, very minute, dispersed or loosely congregated in groups. Colour —Light gray, or light brown when dry. Habitat—Shetland, Mr. C. W. Peach. Examined.—In the dried state. I received three specimens of this interesting species from my friend Mr. C. W. Peach ; they were dredged at Shetland, in 1864, by Mr. J. G. Jeffreys. These specimens are irre- gularly massive, and are nearly of the same size, about three inches at the greatest length; neither of them exhibit evi- dences of a basal attachment, and, it is probable, that they were not attached to any substance at the time they were brought up by the dredge. The dermal membranes have been very nearly destroyed, but in the small patches remaining the characteristic spicula are 7m situ, and in a good state of preservation. ‘The oscula are simple, and rather small, and they do not appear to have been numerous. The pores were well preserved in an open state in some parts of the dermal membrane, and several were clustered together in one of the porous spaces of that organ. The reticulated skeleton is strongly and compactly formed, and the network consists of two or three spicula, or sometimes of a greater number ; the areas are unequal in form, and rather indistinct in some parts. ‘The most striking characters in this species, are those inherent in the dermal and interstitial membranes. In the latter, the sub-clavated cylindrical tension spicula are very nume- rous, and are frequently loosely congregated in fasciculi in greater numbers than can be counted, while others are irre- gularly dispersed around them. ‘The same mode of dis- position prevails with the forcepiform spicula, and it must be remarked that the bases and the apices of the spicula forming a fasciculus are always coincident. JI have never met with this form of spicula before; the nearest approxi- mation is that of the imequi-furcato-triradiate, Figure 237, Plate X, Vol. I of this work; but in this case, there is a 246 A MONOGRAPH OF THE long shaft projected from the semicircular base of the fork. In the spiculum of A. forcipis this shaft is not present. The structure of the forcepiform spiculum is very interest- ing; the semicircular base is much the stouter portion of it, and each limb gradually attenuates to its distal termi- nation, ending in an extremely fine point ; sometimes the limbs are equal in length, but more frequently one is con- siderably longer than the other. In some cases, the two run parallel to each other, but more frequently their distal extremities approach until their apices are in contact, or very nearly so. The minute spines are numerous; they extend over all parts of the spiculum, and the points of nearly all of them are inclined backward towards the semi- circular base of the spiculum. The large bi- and tridentate equi-anchorate retentive spicula are stout, and exceedingly well produced ; the smaller series of bidentate ones are very minute, and the same ob- servation applies to the bihamate spicula. For the distinct exhibition of the spination of the forcepiform spicula and the minute anchorate and bihamate ones, a linear power of 600 or 700 is required. 12. HanicHonDRIA SIMPLEX, Bowerbank. Sponge. Parasitical, coating Zoophytes or Fuci. Surface uneven, rugged. Osculasimple, dispersed. Pores in- conspicuous. Dermal membrane profusely spiculous. Spicula same as those of the skeleton, dispersed, and frequently indistinctly fasciculated. Skeleton. Irregu- lar and diffuse in structure ; rete, spicula few in num- ber, occasionally multispiculous ; spicula acuate, long, and stout, frequently flexuous. Interstitial membrane rarely spiculous; spicula same as those of the skeleton. Colour_—Light gray. Habitat.—Shetland, Mr. C. W. Peach. Examined.—lIn the dried state. BRITISH SPONGIAD&. 247 . This sponge was dredged at Shetland, in 1864, by Mr. J. G. Jeffreys, and preserved for me by Mr. Peach. The specimen is irregularly fan-shaped, an inch and three quar- ters in height, an inch and a half at its greatest breadth, and five lines greatest thickness, and it has been firmly imbedded, apparently during its growth, by juxtaposition, in the substance of a specimen of Halichondria inornatus ; the two sponges in their present dried condition being scarcely to be distinguished from each other, their colour and general appearance being so much alike; but a micro- scopical examination of a small portion of either, immedi- ately discriminates them, H. simplex having the spicula acuate, while those of H. inornatus are spinulate. The organization of this species is exceedingly simple ; one form, only, of spicula, prevailing through all its tissues ; but the large size of those organs, the open diffuse struc- ture of the skeleton reticulations, and the somewhat coarse and profusely spiculous dermal membrane readily serve to separate it from the nearly allied species. 13. HaticHonpria suBDOLA, Bowerbank. Sponge. Ramose, branching irregularly. Surface even, smooth. Oscula and pores inconspicuous. Dermal membrane spiculous. Spicula acuate, minute, and slender, dispersed, very numerous. Skeleton. Rete very delicate and slender, irregular; spicula acuate, long, and slender, variable in size. Colour —Dried, cream white. Habitat—Vazon Bay, Guernsey, Mr. Cooper. Examined.—In the dried state. This little sponge is an exceedingly deceitful subject. In its present condition it looks, at first sight, much like a branch broken off from a small Dictyocylindrus, but the total absence of a peripheral system and of external defen- sive spicula of any kind forbids our assigning it to that 248 A MONOGRAPH OF THE genus, notwithstanding a rather close simulation of the structure of its skeleton. If we examine a longitudinal section in water, the comparatively large quantity of sarcode that surrounds the lines of the skeleton would seem to in- dicate its being a Chalina, of a very delicate structure, but in mounting it in Canada balsam, this simulation of fibre entirely disappears, and we find the skeleton spicula very much longer than are observable in any known species of that genus, and it also lacks the symmetrical arrangement of the parts of the skeleton of Chalina. We are, therefore, under the necessity of considering it as an abnormal form of Halichondria. The sponge consists of a single principal stem, an inch and a half in height, and rather exceeding a line in thickness, from which four small simple branches are given off in an irregular manner; three on one side a little above the middle of the parent stem, and one about half an inch from its base at right angles to the other three, the largest of these being about nine lines in length, with a diameter slightly exceeding half a line. The principal stem of the sponge has lost its natural terminations, the small branches gradually attenuate to rather acute points. From its size, colour, and structure, thus far considered, it might be imagined to be an abnormal form of H. albescens, _ but the difference in the form and size of the spicula at once forbids this conclusion. Neither oscula nor pores could be detected on any part of its surface. Nearly the whole of the dermal membrane has been destroyed ; a small portion of it im a good state of preservation, was crowded with tension spicula, irregularly and closely felted together on all parts of it; the spicula differed from those of the skeleton only, in being shorter and much more slender in their pro- portions. The skeleton is slender and delicate in its struc- ture; the thickest of its lines contains but few spicula, and a great number of them consists of only a single stout spiculum, coated with sarcode. The reticulation has a general tendency of the areas to elongate in the direction of the axis of the sponge, so as to have a faint resemblance to that of the axial cylinder of a Dictyocylindrus. There remained but very slight traces of interstitial membranes, BRITISH SPONGIADA. 249 and in these I did not succeed in detecting any tension or other spicula. 14. Haticnonpria IncRustTANS, Jodnston. Ha icHonpria SABURRATA, Johnston. — PANICEA, Grant, Sponge. Sessile, massive; surface uneven. Oscula dis- persed, large, simple; sometimes more or less elevated. Pores inconspicuous. Dermal membrane thin, pellucid, furnished abundantly with large flat fasciculi of cylin- drical mucronate spicula, and with bihamate simple, reversed, and contort retentive spicula, and also with bi-dentate equi-anchorate spicula. Skeleton. Acuate or subfusiformi-acuate, entirely spined, stout and rather short. Colour.— Buff, yellow or orange colour when alive. Localities. —Frith of Forth, Dr. Grant. Hebrides, Ork- neys and Shetland, Captain Thomas. Welsh and Irish Coasts, Channel Islands, Hastings, &c., J. S. Bowerbank. Examined.—Alive. This is a very remarkable sponge, and will well repay a careful microscopical examination. The spicula of the skeleton ave acuate, and occasionally sub-spinulate, more perhaps from a profusion of spines at the base than from enlargement of that extremity, and all parts of the spiculum are abundantly spinous. The dermal membrane, which can be best obtained at the sides and near the base of the sponge, is thin and transparent, and most profusely fur- nished with large and flattened bundles of cylindrical spicula without spines, but sometimes having their terminations more or less acute instead of hemispherical. In very young specimens the bihamate and anchorate spicula are frequently not to be detected, and the flat fasciculi of spicula on the dermal membrane are sometimes quite detached from each 250 A MONOGRAPH OF THE other, while in mature specimens they are frequently dis- persed in parallel lines in a very regular manner, and in other cases there appears to be no order in their dis- position. The variety of forms of bihamate spicula is greater than I have hitherto found in any single species, and comparatively they are large. Of three specimens in my possession, two of them have the oscula scarcely raised above the general level, while the third has a portion of them considerably elevated on large tumid prominences. My specimens were taken from the east side of St. Katherine’s Rock at Tenby, a little above low-water spring tides. I have one from Mr. M‘Andrew, who dredged it in deep water near Shetland. This species is the one described by Dr. Grant in his admirable papers on ‘The Structure and Functions of the Sponge,’ under the name of S. panicea, in the ‘ Edinburgh New Phil. Journal,’ i, 343, and 1, 138. Dr. Johnston, in his ‘ History of the British Sponges,’ has placed Dr. Grant’s S. panicea as a synonym of H. panicea, Johnston; but as the type of that species is the “sponge-like crum of bread” of Ellis, it is manifest that the synonym is an error. I am indebted to Dr. Grant for one of the original specimens on which he made his observations, and I am therefore enabled to make this correction safely; for although its external characters are not so strikingly developed as in the specimens from Tenby and the Hebrides, its anatomical characters are so peculiar as to leave no doubt on the sub- ject. On examining and comparing the organization of the type specimens of Halichondria incrustans and Hal. saburrata in the Johnstonian collection of British sponges in the British Museum, I found the structural characters to be precisely identical. The author in his specific characters of the latter species, ‘ History of British Sponges,’ p. 120, inadvertently describes the spicula as “short, curved, and double-pointed ;” in page 197 of the same work he corrects this error, and describes them as “short, obtuse at one end and pointed at the other; and, in fact, so like those of Halichondria incrustans, as perhaps to prove that 4. BRITISH SPONGIADS. 251 saburrata may be reckoned a mere variety of the species.” In this supposition I quite concur, and have therefore placed it as a synonym of Hal. incrustans. Not having the advantages of a modern achromatic microscope at the time he made his investigations, my excellent friend Dr. Johnston was unable to detect the spi- niferous character of the skeleton spicula, and the still more minute bihamate and anchorate ones of the dermal membrane. Among the British sponges with which I have been favoured by the late Mrs. Griffith, there is a specimen of HI. incrustans, which was noted as having been “ scarlet but not foetid.” In its dried state the colour was light- yellow, the same as it usually is when ‘in that condition. Montague’s description of this species under the designation of Spongia fava, ‘Wernerian Memoirs,’ vol. ii, p. 115, is exceedingly characteristic of its external appearances under the circumstances described. 15. HanicHonprRia canDipA, Bowerbank. Sponge. Massive, sessile, parasitical on small Fuci or Zoophytes. Surface even sometimes tuberous, minutely hispid. Oscula simple, dispersed, or slightly elevated. Pores inconspicuous. Dermal membrane spiculous ; spicula fusiformi-acuate, smooth, or rarely incipiently spinous near the base, dispersed or diffusely fascicu- lated, numerous ; retentive spicula contort bihamate, small and slender, few in number. Skeleton. Strongly compacted ; rete multispiculous, sides of the areas rarely exceeding one spiculum in length; spicula fusiformi-acuate, short and stout, entirely spined. In- terstitial membranes pellucid, spiculous ; spicula same as those of the dermal membrane, very few in number; retentive spicula contort bihamate, small and slender, few in number. Colour —Alive, milk white. 252 A MONOGRAPH OF THE Habitat.—Dredged off St. Martin’s Point, Guernsey, Rev. A. M. Norman. Examined.—In the dried state. I received eight specimens of this sponge from the Rev. A. M. Norman. None of them exceeded two inches in length or an inch in height. One only had tuberculous elevations on the surface, each terminated by an osculum. In the other specimens the oscula were dispersed irregularly on the surface without elevation, The hispidation of the surface is so minute, that it is only when mounted in Canada balsam that it is apparent; it is produced by radiating fasciculi of the smooth acuate spicula of the dermal membrane, which are projected for about half their length through that organ; sometimes they spring from the skeleton reticulation beneath, but very often they are uncon- nected with it, and are based on the interstitial membranes only. The pores are large, and comparatively few in num- ber. The skeleton is very compactly constructed, the rete often having as many as four or five spicula closely cemented together, and the areas are as frequently trian- gular as they are quadrangular. The interstitial membranes are very translucent, and the sarcode is by no means abun- dant. The tension spicula are of rather rare occurrence, and the retentive spicula do not appear to be nearly so numerous as they are in the dermal membrane. 16. HaLicHonpria IRREGULARIS, Bowerbank. Sponge. Massive, sessile; surface uneven, rugose. Oscula ‘simple, dispersed, small. Dermal membrane pellucid, abundantly spiculous; spicula sub-fusiformi acerate, large, fasciculated and sub-reticulate ; and bidentate angulated equi-anchorate retentive spicula abundantly minute. Skeleton irregular and indistinctly reticulate. Spicula attenuato-acuate, basally and medially spined, stout and rather long. Internal defensive spicula attenuato-acuate, entirely spined, short and: strong. BRITISH SPONGIADA. 253 Interstitial membranes. Tension spicula sub-fusiformi- acerate, same as those of dermal membrane, dispersed. Retentive spicula bidentate angulated equi-anchorate, abundantly dispersed. Colour.—Alive, ochreous-yellow, dry, brown. Habitat—Diamond Ground off Hastings, J. S. Bow- erbank. Examined.—In the living state. This specimen is two and a half inches long, one and a quarter broad, and about three quarters of an inch thick. I received it among several specimens of Halichondria éncrustans of similar size and form, and from which sponges I could not distinguish it excepting by a microscopical examination of its structure. The construction of the skeleton is very loose and irregular, and from the abundance of the large acerate tension spicula the sponge may, by a hasty examination, be easily mistaken for a Hymeniacidon; but its true structure is readily demonstrable when mounted in Canada balsam, by the aid of a power of about 300 linear. The skeleton spicula, and the internal defensive ones, very closely resemble each other, but the latter are very little more than half the length of the former, and although smaller, the spination stronger and more abundant than those of the skeleton, and their spination is entire from base to apex, while the apical third of those of the skeleton are usually entirely free of spines. The retentive spicula are minute, but proportionally stout, and are very abundaht on all parts of the membranous tissues of the sponge. 17. Haxuicnonpria Dickiel, Bowerbank. Sponge. Coating (?); surface smooth. Oscula simple, dispersed, small. Pores inconspicuons. Dermal membrane pellucid, abundantly spiculous; spicula mucronato-cylindrical, occasionally sub-clavate-hastate fasciculated. Skeleton spicula acuate entirely spined.. 254 A MONOGRAPH OF THE Retentive spicula bidentate and tridentate equi- anchorate, abundant and frequently very large, dis- persed. Colour.— When dried, deep nut-brown. Habitat.—Strangford Lough, Professor Dickie. Examined.—In the dried state. I am indebted to Professor Dickie for a fragment of this species, about three quarters of an inch in diameter, and the eighth of an inch thick. This sponge differs greatly in external appearance from HHalichondria incrustans, although in the structure of the skeleton and in the forms of the skeleton and dermal spi- cula there is a close approximation to each other. ‘The most striking difference between the two species exists in the characters of the retentive spicula. In A. Dickiei the anchorate spicula are very much larger and greatly ex- ceed in number those in H. incrustans, and in the former there is a total absence of bihamate spicula, while in the latter species they are very numerous and various in form, so that these structural differences in addition to those of external character will enable the student to readily distin- guish the two species. The vast quantity and great size of many of the ancho- rate spicula is a very remarkable feature in this sponge. The inner surface of the dermal membrane is literally crowded with them, attached to the membrane by the middle of the convex surface of the curved shaft, while the terminal flukes are thrown upward into the sarcode. They are dispersed evenly over the whole surface of the mem- brane without the slightest indication of order or arrange- ment. They are very abundant also on the interstitial membranes, but not to so great an extent as onthe dermal one. ‘These spicula in the specimen under consideration are found in all stages of development, from the young and slender curved shaft, with scarcely an indication of the terminal flukes, to the strong and fully developed spiculum, with the flukes nearly a third of its entire length. BRITISH SPONGIADA. 255 The tension spicula of this species present valuable dif. ferential characters, their sub-clavate or hastate termination, readily distinguish this species from the nearly allied ones of H. incrustans and H. Batei, in the tension spicula of which species, these peculiarities of termination never occur. 18. Haticnonpria Parrersoni, Bowerbank. Sponge. Coating (?); surface smooth, minutely corru- gated. Oscula simple, dispersed. Pores inconspi- cuous. Dermal membrane pellucid, abundantly spi- culous; spicula cylindrical, incipiently terminally spined, fasciculated loosely and irregularly. Skeleton spicula acuate, entirely spined, rather stout. Reten- tive spicula angulated, dentato-palmate inequi-ancho- rate; distal palm about half the length of the spi- culum, solitary and very few in number. Colour —Nut-brown in the dried state. Habitat.—Strangford Lough, Professor Dickie. Examined.—lIn the dried state. Iam indebted to my friend Professor Dickie, of Aber- deen, for my knowledge of this species. I received from him four fragments, the largest of which was nine lines in length by four in breadth, and about one line in thickness, and there is every appearance of its having coated a flat and even surface. A few fragments only of the dermal membrane were left upon the sponge, but the positions of the oscula were distinctly indicated by the terminations of the excurrent canals at the surface of the sponge. ‘Ihe spicula of the skeleton are similar in form and spination to those of H. incrustans and H. Dickiei, but they are smaller by about one fourth of the length of the latter; but the essential difference from the above-named two species exists in the incipient spination of the termination of the tension spicula, which are distinctly seen with a power of about 300 linear, and in the form of the anchorate retentive spicula, which are very few in number, and which can only 256 A MONOGRAPH OF THE be seen “in situ when immersed in Canada balsam, the sarcode being abundant and of a deep brown amber colour. I have named this species in honour of my friend Mr. Robert Patterson, of Belfast, whose valuable labours for the advancement of zoology are too well known to need any eulogy from me. 19. HaticHonpRIa PULCHELLA, Bowerbank. Sponge. Massive, sessile; surface uneven, smooth. Os- cula simple, dispersed. Pores inconspicuous. Dermal membrane smooth, abundantly spiculons; spicula sub-fusiformi cylindrical, terminations incipiently and very minutely spinous ; dispersed or very loosely fas- ciculated, numerous, ‘Tension spicula cylindrical, very long, and extremely slender, rather numerous. Retentive spicula simple bihamate, small and slender, few in number. Skeleton compact ; rete multispicu- lous, spicula sub-fusiformi acuate, rather stout and short, incipiently spinous. Interstitial membranes rather abundantly spiculous ; tension spicula same as those of the dermal membrane; retentive spicula simple bihamate, small, and slender, very rare. Colour.—Nut-brown when dried. Habitat—Guernsey, Rev. A. M. Norman. Examined.—lIn the dried state. The specimen has apparently been based on a small fragment of a bivalve shell, and was composed of two specimens united by a very small portion of their surfaces. ‘The largest of the two is somewhat fan-shaped, seven lines in height, an inch in breadth, and about four lines in thickness. The form of the second specimen is very nearly the same as that of the first. The oscula are small, and require the aid of a lens of an inch focus to render them distinctly visible. The dermal membrane and its spicula afford the most prominent of the specific characters ; the sub-fusiformi cylindrical spicula have their terminations BRITISH SPONGIADS. 257 slightly dilated, and frequently exhibit very faint traces of incipient spination, requiring a linear power of about 700 to render it visible. ‘These spicula are about the same length as those of the skeleton, but not above half or two thirds of their diameter. ‘Their mode of disposition in the dermal membrane is very irregular; sometimes they are congregated in considerable numbers in broad flat fasciculi, in others, the bundle consists of two or three spicula only, and single spiculum are also abundantly dispersed, lying in every direction in the spaces between the fasciculi. ‘I'he long slender tension spicula are faintly visible in a specimen mounted in Canada balsam; they are rather numerous, and are about equally dispersed in all parts of the mem- brane, but im a specimen mounted in water they are not visible. The same may be said of the retentive spicula which are very few in number. The tension spicula are so extremely attenuated that they require a power of at least 700 linear to render the form of their terminations distinctly visible; they are abundant in the interstitial membranes, while the retentive spicula are so few in number as to be very rarely detected. The spination of the skeleton spicula is by no means regular; sometimes the spines are thinly distributed over the whole of the spiculum, in others they are basally and apically spinous, and occasionally they are only basally spinous, and in all they are in so incipient a state as to be nearly invisible when immersed in the sarcode, even when mounted in Canada balsam, and it is only after being separated from the tissues by the aid of nitric acid that their characters are rendered distinctly visible. There are only two sponges with which this species may probably be confounded, H. Jngalli and H. Pattersoni. In the former species the skeleton spicula, although of the same form are very much smaller and more slender than in H. pulchella, and in the latter they are much larger, and have their spination more boldly produced than in the sponge under consideration. ‘The total absence also of anchorate spicula in A. pulchella serves also to render its separation more complete. 17 258 A MONOGRAPH OF THE 20. Haticnonpria Ineauui, Bowerbank. Sponge. Sessile; closely latticed by round or com- pressed inosculating branches. Surface uneven, slightly and minutely hispid. Oscula simple, nume- rous, dispersed, minute. Pores inconspicuous. Dermal membrane thin, pellucid, furnished with slender sub- fusiform cylindrical spicula which are fasciculated, forming a coarse and irregular network; and rarely with malformed bihamate, and angulated inequi-an- chorate spicula. Sarcode abundant, gelatinous. Ske- leton. Spicula attenuato-acuate, basally spined, and rarely attenuato-acerate, medially spined. Intersti- tial membranes furnished with dispersed, slender, sub-fusiform, cylindrical spicula like those of the dermal membrane. Colour.—Nut-brown, alive. Dark brown when dried. Habitat.—About one mile off Castle Hill, Hastings, J.S. Bowerbank, Moray Frith, Rev. Walter Gregor. Evamined.—Alive. The latticed form of this sponge approaches somewhat to that of Chalina Montaguii, but the colour and surface characters of the two species are so different as to cause them to be readily distinguished from each other. ‘Ihe rough and slightly hispid character of the surface in either the fresh or dried state is apparent by the aid of a lens of an inch focus, and beneath a power of about 100 linear the latter character is seen to be produced by the protrusion beyond the surface of the dermal membrane of portions of the fasciculi of the skeleton. The larger oscula are barely to be seen by the unassisted eye, and the greater portion of them require the aid of a lens of an inch focus to render them distinctly visible. The dermal membrane is furnished abundantly with fasciculi of slender cylindrical or sub- BRITISH SPONGIADA. 259 fusiformi-cylindrical spicula forming a coarse irregular net- work, and occasionally these spicula exhibit a slight ten- dency to clavate terminations; the malformed bihamate spicula are few in number, and the angulated inequi-an- chorate ones are very rare. ‘The sarcode is abundant, and abounds with minute vesicles or cytoblasts and molecules of various sizes. It appears to entirely fill the interstitial spaces, and the interstitial membranes are also thickly covered by it. The attenuato-acuate spicula of the skeleton are singular from the unusual irregularity of their form, near the basal termination, arising from the numerous and strongly pro- duced spines with which they are thickly covered, so that in many cases that portion of the shaft has an irregular and distorted appearance. A few attenuato-acerate spicula are found intermixed with the attenuato-acuate ones, and these acerate spicula are medially but not terminally spined. This sponge was brought up by the trawl about a mile off shore opposite to the Castle Hill. I have named it after my late friend Mr. Thomas Ingall to whom I am indebted for many interesting specimens of sponges from the British Channel, and for much kind assistance during the course of my studies of the British species. Since writing the above, I have found a second specimen on the shore. It agrees in its external characters and size with the first one, but is less latticed in its form; when preserved in strong salt and water it becomes of a dark purple colour. I subsequently received this sponge in a young state, in the form of a very thin dark stratum on the surface of a fragment of a large bivalve shell dredged by the Rev. Walter Gregor of Macduff, in the Moray Frith. 21. Hanicnoncria scaNDENS, Bowerbank. Sponge. Coating, parasitical. Surface smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal 260 A MONOGRAPH OF THE membrane pellucid, furnished abundantly with large fusiformi-cylindrical tension spicula terminally spined, loosely fasciculated or dispersed, as long as those of the skeleton: also abundantly with simple bipocillated anchorate spicula, and sparingly with dentato-palmate and bidentate inequi-anchorate spicula. Skeleton. Spicula fusiformi-acuate, basally and apically spined, stout. Interstitial membrane. ‘Tension spicula same as those of dermal membrane, very abundant, dis- persed ; also with simple bipocillated, dentato-palmate and bidentate inequi-anchorate spicula sparingly. In- ternal defensive spicula, acuate, entirely spined, short and stout, very few in number. Colour.—Alive, vivid greenish blue. Nut-brown when dried, Rev. A. M. Norman. Hatitat.—Shetland, Rev. A. M. Norman. Examined.—In the dried state. This sponge is parasitical on a slender branching Zoophyte running over every part of it and coating the branches to the thickness of about a line, the entire diameter rarely appearing to exceed two lines; where the dermal membrane was preserved, the surface appeared smooth and even. The large fusiformi-cylindrical tension spicula are very abundant in some portions of the dermal membrane, fre- quently completely covering a considerable space, arranged in parallel order, or in broad flat fasciculi. The simple bipocillated anchorate spicula were exceedingly numerous in some parts of the inner surface of the dermal mem- brane and a few contort and umbonated forms were mingled with them. The pocillated anchorate spicula were many of them attached to the membrane by the middle of the back of the shaft, but the greater number were lying side- ways. ‘The interstitial membranes were very sparingly furnished with these forms. The dentato-palmate inequi- anchorate spicula are very irregular in their form. The small basal end is remarkably angular, forming nearly an equi-angular triangle, the lateral portions forming two of BRITISH SPONGIADZ. 261 the angles, and the basal tooth the third one, all three being very small, while the apical palm extended over more than half the length of the spiculum. ‘lhe relative pro- portions of the bidentate inequi-anchorate ones are very similar to those of the palmated anchorate spicula; both sorts were attached to the dermal membrane by the ex- ternal surface of the middle of the shaft, and not by the small basal end as in cases where such forms are congregated in rosette-like groups. The skeleton spicula vary somewhat in the amount of their spination ; sometimes they are only basally spined, and occasionally the middle of the shaft exhibits an incipient spination, but the general character of the spination is basally and apically. ‘The large fusiformi-cylindrical ten- sion spicula are very abundant in the interstitial portions of the sponge, crossing the areas of the skeleton in every direction, and sometimes becoming associated with the skeleton spicula in its network. ‘The internal defensive spicula are not half the length of the skeleton ones; their spination is complete and more proininent, especially at the base. 22. Haricnonpaia Batur, Bowerbank. Sponge. Massive, sessile. Surface smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane spiculous; spicula acuate, apices obtuse ; loosely fasciculated. Skeleton. Spicula acuate, stout ; entirely and profusely spined ; spines minute. Re- tentive spicula very large; and small, bidentate equi- anchorate, rarely tridentate, very numerous. Colour.—Light brown in the dried state. Hatitat.—Shetland ? Mr. Spence Bate. Ezxanuned.—In the dried state. This sponge is a small irregular mass, seated on a piece of stone near the base of a specimen of JIsodictya in- 262 A MONOGRAPH OF THE Sundibuliformis, Bowerbank, and leaning against a young specimen of Dictyocylindrus, Bowerbank. It is in a very imperfect condition, and does not exceed half an inch in diameter. It belongs to the museum of Natural History at Plymouth. In its structure, it is very closely allied to Halichondria Dickiei of this work; but so far as we can judge by the specimen under consideration, it does not ap- pear to bea coating sponge. Instructural character, with- out a careful examination, itis very difficult to discriminate be- tweenthem. ‘The skeleton spicula in both species are acuate and entirely spined, but those of Hal. Dickie are the more slender of the two in their proportions. ‘The most striking specific difference exists in the tension spicula, which never present the sub-clavate or hastate terminations, which are so characteristic in those of the last-named sponge. Nordo we find the decided mucronation of both terminations as in those of Hal. incrustans. The tension spicula vary to some extent in their form ; occasionally, the base exhibits a slight mclination to mucronation, and sometimes the apex is so obtuse as to almost give the spiculum the character of the cylindrical form; but the prevailing shape is that of a rather obtusely terminated acuate spiculum. The retentive spicula, like those of Hal. Dickiei, are ex- ceedingly numerous on the inner surface of the dermal membrane, as well as on the interstial ones ; and the larger and smaller series are indiscriminately crowded together. No simple or contort bihamate spicula could be detected. I have dedicated this species to my friend Mr. Spence Bate, who has laboured so long and so efficiently in the cause of Marine Natural History, and to whom I am in- debted for my first acquaintance with this sponge. 23. HALICHONDRIA GRANULATA, Bowerbank. Sponge. Massive, sessile. Surface somewhat rugged. Oscula simple, small, numerous, dispersed. Pores in- conspicuous. Dermal membrane simple, pellucid ; furnished with sub-mucronate-cylindrical spicula, and BRITISH SPONGIADA. 263 with large and small bidentate equi-anchorate spicula, irregularly dispersed. Skeleton. Spicula acuate, stout, entirely, but incipiently spined. Internal de- fensive spicula; sub-spinulate attenuato-acuate, en- tirely, but incipiently spined. Interstitial membranes, Tension spicula, acuate, slender, incipiently and en- tirely spined ; and sub-mucronato-cylindrical, smooth and slender. Retentive spicula; large and small bidentate equi-anchorate spicula. Colour.—In spirit, brownish red. Locality. Oban, Mr. Joshua Alder. Examined.—From spirit. I am indebted for the only specimen of this species to Mr. Joshua Alder, of Newcastle-on-'l'yne, who obtained it at Oban. It is nearly hemispherical in form, and is not quite three quarters of an inch in diameter at its base. In the wet state, the surface presents a granulated appear- ance. ‘Ihe anchorate spicula on the inner surface of the dermal membrane are attached at the middle of the outer curve of the bow of the spiculum, so that both of the fluked terminations are immersed in the surface of the body of the sponge, and are equally well produced. The small acuate spined and attenuated spicula closely resemble those with which many species of fibrous sponges are armed, and which are based in those species in the fibre, and pro- ject at about right angles from it into the canals, and it is probable they perform a similar defensive office in this species ; but I could not find them zm situ, although they are tolerably abundant among the others when liberated from the animal by boiling in nitric acid. I have, there- fore, assigned them to the skeleton as defensive spicula by analogy only. The sarcode is abundant and deeply coloured, and abounds in granular molecules. 264 A MONOGRAPH OF THE 24. Harticuonpria Hynpmani, Bowerbank. Sponge. Branching and anastomosing from numerous small attenuated bases ; branches slightly compressed, terminations corymbose. Surface rugose, hispid. Oscula and pores inconspicuous. Dermal membrane thin, transparent, furnished with a few, dispersed bidentate imequi-anchorate retentive spicula. Skele- ton. Spicula attenuato-acuate, semi-spined basally, somewhat stout. Internal defensive spicula attenuato- acuate, entirely spined, few in number. Interstitial membranes. ‘Tension spicula cylindrical, slender and flexuous ; retentive spicula bidentate inequi-anchorate, minute, dispersed ; and simple and contort bipocil- lated anchorate spicula, minute, dispersed. Sarcode abundant, dense and purple in the dried state. Colour.—Alive, light yellow, Rev. Walter Gregor; purple, J. S. Bowerbank. In spirit, dark purple; when dry, brown, with a tinge of purple. Habitat.—Strangford Lough, Messrs. G. C. Hyndman and Wm. Thompson. Moray Frith, Rev. W. Gregor. Hastings, J. S. Bowerbank. Examined.—F¥rom spirit, alive, and dry. This highly interesting little sponge was dredged in Strangford Lough, in June, 1846, by Messrs. Hyndman and Thompson, in from fifteen to twenty fathoms water ; it is based on the shells of Pecten opercularis. The largest specimen is one and three quarters inches in length by one and a quarter inches wide, and one inch in height. It was attached to the shell by a number of small basal points; but the whole by anastomosis forming one sponge. In several other smaller specimens the same peculiarities of character exist. The termination of each branch of the sponge is corymbose, and the terminations of the whole, as BRITISH SPONGIADZ. 265 regards each other, are also corymbose. The inequality in the size of the flukes of the inequi-anchorate spicula of the dermal membrane is quite as great as those in the similar membrane of Halichondria lingua, but they are very much fewer in number, and very minute; and I could not de- tect any such symmetrical arrangement of them as exists in H. lingua. The internal defensive spicula are com- paratively few in number ; they may be readily distinguished from those of the skeleton, from being not more than about half their length, and from being spinous from base to apex, while the distal half of those of the skeleton is without spines. The membranous interstitial structure is abun- dantly furnished with very minute bidentate inequi-anchorate spicula, which are not readily to be seen iz situ, until a minute portion of the sponge has been mounted in Canada balsam, they are then seen most frequently attached to the membrane by the middle of the back of the bow of the spiculum ; they are disposed without order, and are so minute as to require a linear power of from 600 to 700, to render them visible. The varieties in the form of the bi- pocillated spicula is very great, scarcely any two being precisely alike in the extent or mode of their develop- ment. I obtained a specimen of this sponge at Hastings, thinly coating the two valves of a specimen of Pecten opercularis. In this form, it very closely resembles a Hymeniacidon in its structure, exhibiting very indistinct traces of reticulated skeleton ; but in every other organic structure it agreed perfectly with the Strangford Lough specimens. It was taken in trawling at the Diamond Fishery Ground, off Hastings, in February, 1862. Its colour was dark purple. I have also received two specimens dredged in the Moray Frith, by the Rev. Walter Gregor, of Macduff, six miles off shore, in forty-two fathoms, one of these specimens is parasitical on a small branching Fucus, covering it com- pletely, and thus in its general contour closely resembles a small Dictyocylindrus. ‘The other coats all parts of a small Zoophyte, confusedly matted together. The external form appears to be subject to very great variations dependent 266 A MONOGRAPH OF THE on the substances on which the sponge may happen to be based. The specimens were labelled ‘Colour, light yellow.” I have dedicated this interesting species to Mr. Geo. C. Hyndman, of Belfast, who in conjunction with my late lamented friend Mr. Wm. Thompson, has done so much to diffuse a taste for Natural History in Ireland, and to whom also, I am indebted for much valuable information and assistance regarding the Irish specimens of the Spongiadee. 95. HaLIcHONDRIA NIGRICANS, Bowerbank. Sponge. Massive, sessile, compressed; surface uneven, somewhat rough. Oscula small, simple, nume- rous. Pores inconspicuous. Dermal membrane thin, pellucid ; furnished with terminally spined sub-fusiform cylindrical spicula, irregularly disposed in fasciculi, and with palmato-inequi-anchorate, dentato-inequi- anchorate, and sparingly with minute inequi-bipocil- lated spicula. Interstitial membranes furnished with the same spicula as those of the dermal membrane. Skeleton. Spicula acuate, entirely spined, stout. Sarcode abundant, dark-coloured, abounding in com- pressed cytoblasts or cells. Colour.—Alive and dried very dark purple. Habitat—Orkney (?) or Hebrides (?), Mr. McAndrew ; Strangford Lough, Professor Dickie ; Hastings, J. S. Bower- bank. Examined.—In the living and dried states. The specimen upon which this species is based is but a fragment. I found it among a large quantity of specimens of zoophytes, sponges, and other marine animals in the possession of my friend Mr. McAndrew, at Liverpool, who stated that they were part of the results of his dredgings near the Orkney Islands and the Hebrides. It is one inch BRITISH SPONGIADS. 267 in length, half an inch in height, and rather less than a quarter of an inch thick at the lower edge, and gradually becomes thinner towards the upper edge; one end is de- cidedly a fractured one, the other appears to be a natural termination ; the characters, therefore, of form and attach- ment require confirmation from more perfect specimens. The oscula are also rather indistinctly characterised, as ex- hibited by this mutilated specimen; they are simple, small, and irregular in form, and a few only are really conspicuous without the aid of a lens. The dermal membrane is pel- lucid, but the inner surface is abundantly covered with the dark-coloured sarcode. The terminally spined sub-fusiformi-cylindrical spicula are disposed in irregular fasciculi, and from the indistinctness of the tissues arising from the dark-coloured sarcode, they may be readily mistaken for portions of the network of the skeleton immediately beneath. The palmato- and dentato-inequi- anchorate and inequi-bipocillated spicula are irregularly dispersed in both the dermal and interstitial membranes ; the former two did not appear in any instance to be at- tached to the membranes by the smaller termination, as might have been expected from their form, but in every instance observed, the attachment was at about the middle of the bow of the spiculum. It was with much difficulty that I found the inequi-bipocillated spicula im situ on the interstitial membranes ; the larger end appeared to project slightly above the surface of the sarcode, but the line of projection was not in any one of the three I observed at right angles to the plane of the membrane. I did not detect them zz sifu in the dermal membrane, but I have no doubt that they belong to it as well as to the interstitial ones. This and H. Hyndmani are the only British sponges in which I have yet found this very minute and singular form of spiculum, which requires a power of 400 linear to render it distinctly visible. ‘The dimensions of an averaged sized one which I measured was length ;4,nd inch ; diameter of largest termination ;,nd inch; diameter of smallest termination ;4,rd inch, while the anichorate spicula, although small of their kind, measured in length ;},th inch. 268 A MONOGRAPH OF THE The terminally spined sub-fusiform cylindrical spicula are more sparingly dispersed in the interstitial membrane than they are in the dermal one, and they are very rarely col- lected in fasciculi. The compressed cytoblasts or cells of the sarcode are abundant throughout the whole of that substance; some of them exhibited a nucleated appearance. The diameter of an average sized one that I measured was ,¢,rd inch. I have since received this species from Professor Dickie who dredged it in Strangford Lough. This specimen coated a valve of Pecten opercularis for the thickness of rather more than the eighth of an inch, and I have also obtained numerous specimens coating the valves of Pecten opercu- laris from the Diamond Ground, off Hastings, the sponge in some cases being nearly three fourths of an inch in thickness, and in others not exceeding the thickness of stout paper; when in the latter state, the sponge may be readily mistaken for a Hymeniacidon. 26. HaLICHONDRIA ALBULA, Bowerbank. Sponge. Coating, very thin; surface smooth and even. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane translucent, abundantly spiculous ; spicula equally dispersed ; acuate, entirely spined, large, and stout ; spines conical, stout, and long. Skeleton. Spicula, acuate, long, and slender. Spicula of inter- stitial membranes same as those of dermal membrane. Retentive spicula bidentate, equi-anchorate, few in number. Colour.—White, in the dried state. Habitat.—Shetland ; deep water, Mr. Barlee. Examined.—In the dried state. This remarkable little sponge is in the form of a very thin crust on the distal margin of the imperforated shell of a small Terebratula caput-serpentis, Lam. It covers a space BRITISH SPONGIADA. 269 not exceeding two and a half lines in length by one in breadth, and it looks exceedingly like a stain of thin white- wash on the margin of the shell which does not exceed five lines in length. None of the oscula were open, but their situation was well indicated by a concentration of the dermal spicula in a radial form at particular spots on the dermal membrane, in all other parts of which the spicula were irregularly but equally dispersed. The tension spi- cula of the dermal and interstitial membranes are remark- ably large and stout as compared with those of the skeleton, which although much longer, are not above half the dia- meter of the dermal ones. ‘The skeleton in the portion examined formed but a very small part of the sponge, and was represented by a few straggling fasciculi of spicula ; the sponge being, in truth, mainly composed of dermal and a few very shallow interstitial membranes with a very thin layer of skeleton fasciculi, the thickness of the whole being less than that of writing paper. From the paucity of the skeleton in this specimen it is probable that the sponge is not an adult, and that when fully developed the reticulated skeleton would be more abundant. Iam indebted to the kindness of my late friend Mr. Barlee for this singular and interesting little species. He dredged it in deep water at Shetland. 27. HaLICHONDRIA FARINABIA, Bowerbank. Sponge. Coating, thin; surface smooth and even. Os- cula numerous, simple, minute, dispersed. Pores in- conspicuous. Dermal membrane pellucid, furnished abundantly with slender spinulate spicula, and more sparingly with small inflato-cylindrical tension spicula. Skeleton rete slender, areas irregular, open, and dif- fuse ; spicula spinulate, small, and slender. Colour.—Liviug, deep orange or scarlet. Dried, ochreous yellow. 270 A MONOGRAPH OF THE Habitat—On Pecten opercularis, five fathoms, Belfast Bay, Mr. William Thompson. Isle of Cumbrae, Clyde, Rev. A. M. Norman. Diamond Ground, off Hastings, J. S. Bowerbank. Ezamined.—In the living and dried states. The first specimen of this sponge was sent to me by my late friend, Mr. William Thompson, of Belfast, who dredged it in April, 1848, in five fathoms water, in Belfast Bay. I have received it also from the Rev. A. M. Norman. In both cases it is exceedingly thinly spread over the sur- face of one or both valves of Pecten opercularis and does not exceed half a line in thickness in any specimen that I have seen. Mr. Thompson describes the colour of the sponge as “reddish orange when recent.” The Rev. Mr. Norman as “scarlet when living.” In four specimens I have examined in the dried state, the colour is ochreous yellow, and all of them appear as if the shells had been washed over with a thick infusion of yellow meal and then dried. The oscula are not visible without the aid of a lens of about two inches focus, and many of them are so minute as to be scarcely discernible with that power; they are numerous, and dispersed over all parts of the sponge, I could not detect any open pores with a power of 160 linear. The dermal membrane is furnished abundantly with spinulate spicula which are thickly matted in its inner surface ; they are much shorter and more slender than those of the skeleton, a few of which are intermixed with them and closely imbedded in the same surface ; there are nume- rous small inflato-cylindrical spicula. I do not recollect having before found the small inflato- cylindrical spicula in any other sponge excepting Chalina ficus, on the dermal membrane of which they are exceed- ingly numerous; they are nearly of the same size in both sponges, but very much less in number in the species under consideration. On the external surface of the sponge sent to me by BRITISH SPONGIADA. 271 My. Norman, there are a number of dark oval bodies apparently ova of some Zoophyte, but I could find none of them in the substance of the sponge, nor did I observe them on the specimen from Mr. Thompson. I conclude, therefore, that they do not belong to the sponge. I obtained numerous specimens of this sponge coating Pecten opercularis at Hastings, 1862. They were taken by the trawlers at the Diamond Ground, about ten miles off that town. The whole of them when alive were of a reddish orange colour; when dried, they were all of an ochreous yellow. 28. HaticnonpRia InorNATUS, Bowerbank. Sponge. Amorphous, parasitical on Zoophytes or Fuci; somewhat compressed. Surface irregular, smooth. Oscula simple, dispersed. Pores inconspicuous. Dermal membrane reticulated, rete very large and strong, multi-spiculate ; spicula same as those of the skeleton; areas abundantly furnished with tension spicula of the same form as those of the skeleton ; and also with simple and contort minute bihamate retentive spicula. Skeleton irregular and diffuse in structure ; rete strong and multispiculous; spicula sub-fusiformi-spinulate, stout, and rather long. In- terstitial membranes abundantly spiculous ; tension spicula same as those of the skeleton; retentive spi- cula, simple and contort minute bihamate spicula. Colour.—Dried, dirty gray. Habitat.—Shetland, Mr. C. W. Peach. Eaxamined.—In the dried state. This sponge was dredged at Shetland, in 1864, by Mr. J. Gwyn Jeffrey, and was preserved for me by Mr. Peach, who accompanied the expedition. The specimen is some- what compressed. It is three inches in length, two inches 272 A MONOGRAPH OF THE broad, and six lines in thickness ; and when examined in the dried state with a two inch lens, the appearance is much that of a mass of tow wetted, closely compressed, and dried in that state. This appearance is produced by the large size of the reticulations of the dermal membrane, the areas of which are very open and irregular in form, and the rete very stout. The tension spicula are very abundant in the membranes of the areas, but the retentive spicula are few in number. The spicula of the rete are compactly fasciculated together. Numerous minute circular nucleated cells were imbedded in the sarcode on the inner surface of the dermal membrane. ‘The reticulations of the skeleton are strongly and compactly constructed, but not to quite so great an extent as in the dermal membrane. The profusion and large size of the retentive spicula of the interstitial membranes frequently give the whole of that portion of the skeleton in the field of view the aspect of a Hymeniacidon, but the definite fasciculation of the skeleton in other parts corrects that illusion. The retentive spicula appear to be more abundant in the interstitial membranes than in the dermal one, and the nu- cleated cells are as numerous in the interstitial membranes as in the dermal membrane. On the side of this specimen is firmly imbedded the type specimen of Halichondria simplex ; both having lo- cated themselves on the same Zoophyte, a Tubularia; they have been closely pressed together by juxtaposition and progressive development. It is a singular accident that two new species should thus be found conjoined. BRITISH SPONGIADA. Isopictya, Bowerbank. Section * Skeleton spicula, acerate. i, 2 3. 4. 5. 6 7 8 Soe eee ee SCaANaATPE WMHS Oo! Isodictya cinerea, Bowerbank. Peachit, Bowerbank. permollis, Bowerbank. simulo, Bowerbank. varians, Bowerbank. rosea, Bowerbank. elegans, Bowerbank. McAndrewti, Bowerbank. indefinita, Bowerbank. parasitica, Bowerbank. indistincta, Bowerbank. densa, Bowerbank. anomala, Bowerbank. simplex, Bowerbank. jugosa, Bowerbank. pallida, Bowerbank. Jistulosa, Bowerbank. Gregorii, Bowerbank. Jallax, Bowerbank. robusta, Bowerbank. pocillum, Bowerbank. mammeata, Bowerbank. simulans, Bowerbank. dichotoma, Bowerbank. -palmata, Bowerbank. pygmea, Bowerbank. ramusculus, Bowerbank. clava, Bowerbank. 18 273 274 A MONOGRAPH OF THE Szcrion * * Skeleton spicula, acuate. Sub-section A, Skeleton spicula, smooth. 29. Jeaunciye infundibuliformis, Bowerbank. 30. cdissimilis, Bowerbank. 31. — Normani, Bowerbank. 32. — fucorum, Bowerbank. 33. — Alderi, Bowerbank. 34. — Kdwardii, Bowerbank. 35. — lobata, Bowerbank. 36. — paupera, Bowerbank. 37. — uniformis, Bowerbank. 38. — Clarkei, Bowerbank. 39. — — gracilis, Bowerbank. 40. — Barleei, Bowerbank. Sub-section B, Skeleton spicula, spinous. Al. Isodictya Beant, Bowerbank. 42. — lurida, Bowerbank. 43. — fimbriata, Bowerbank. 1. Isopictya CINEREA, Bowerbank. SPONGIA CINEREA, Grant. HaLicHONDRIA CINEREA, Fleming. — — Johnston. Srone1a SOWERBII, Leming. Sponge. Coating; surface even, smooth. Dermal mem- brane pellucid, aspiculous. Oscula simple, dispersed, few in number. Pores inconspicuous. Skeleton unispiculous, spicula acerate, rather long and stout. Interstitial membranes. ‘Tension spicula slender, few in number. Gemmules membranous, aspiculous. BRITISH SPONGIADA. 275 Colour.—Alive, lilac colour. Rev. A. M. Norman. Dry state, light fawn yellow. Habitat.—Frith of Forth, Dr. Grant. Peterhead, Mr. Peach. Chudleigh Salterton, Rev. A. M. Norman. FExamined.—tIn the dried state. This sponge is apparently a rare species. Dr. Grant states that he had met only with a single specimen from the Frith of Forth, and Dr. Johnston describes the speci- men from which he drew up his character as containing a piece of Zostera marina, from which he infers it is a littoral species. I have been unable to detect the Zostera marina in any of the specimens at the British Museum. In the Johnstonian collection of British sponges in the British Museum there are four small specimens arranged on one board, which are labelled Halichondria cinerea. Two specimens are upon one piece of card marked 17°, and the other two are respectively marked 17° and 17°. On examining each of them carefully I found them to be four distinct species of the genus Isodictya of this work, with two of which, one of those marked 17°, and the one marked 17°, I was previously acquainted; the remaining two specimens, one marked 17°, and the other 17°, were new to me; under these circumstances I found it was im- possible to decide which of the four was the type of the sponge designated by Dr. Grant as Spongia cinerea. I therefore at once applied to that learned naturalist to assist me to a correct determination of the species in the event of its having been preserved in his cabinet: fortunately this was the case, and he responded to my request by kindly sending me a portion of the type specimen described in his works. On carefully comparing its structural characters with those of the four specimens marked Halichondria cinerea in the Johnstonian collection, I found that the one marked 17° was identical in structure with the type speci- men in the cabinet of Dr. Grant. In the dried condition of the four sponges thus ex- hibited in the national collection, it would be impossible to distinguish the species by the unassisted eye; but a close 276 A MONOGRAPH OF THE inspection of their structural peculiarities enables us readily to surmount the difficulty, for although the structure of the skeletons very closely resemble each other, there are very distinct differences in the length and proportions of the spicula of which they are composed. ‘The presence of acuate spicula in J. varians readily separates it from the other three, but in these the forms of the spicula are very nearly alike. ‘Their real differential characters exist in the differences in their proportions. Thus,in J. permollis we have the spicula .,th inch in length, and ;4,th inch in diameter ; and in J. Peachii st inch long, and ,',rd inch in diameter ; the latter agreeing nearly in length, but not having half the amount of the diameter of the former. While in I. cinerea the dimensions of the spicula are ,j;th inch in length, and ,3,th inch in diameter, agreeing nearly in diameter with those of JZ. permollis, but being almost half as long again as the spicula of that species. The specimen sent to me by my kind friend Mr. Peach was found attached to the stalk of a large Fucus at Peterhead, North Britain. It is thirteen lines in length, by seven in breadth, and about two in thickness. I have also been favoured, by the Rev. A. M. Norman, with the loan of a specimen from Chudleigh Salterton, which agrees in all its essential characters with that from Mr. Peach ; but it is rather the thicker of the two, and has a brighter and more decidedly yellow colour. Mr. Norman has also obtained a specimen from Seahouse, County Durham. In one of Mr. Norman’s specimens the gemmules are abundant beneath the dermal membrane, they are more or less spherical, and of a deep amber colour; one of them, apparently a full-sized and matured one, was filled with minute spherical vesicles. It measured ,;st inch in dia- meter. 2. Isopictya Peacam, Bowerbank. Sponge. Encrusting, surface smooth. Oscula simple, minute, few in number. Pores inconspicuous. Der- BRITISH SPONGIADA. 277 mal membrane abundantly spiculous, reticulated ; rete unispicular, with numerous dispersed spicula fre- quently intermixed with the reticulations. Skeleton. Reticulations diffused and open or unispiculous ; spicula sub-fusiformi-acerate, small and slender. In- terstitial membranes. ‘Tension spicula, sub-fusiformi- acerate, very slender, few in number. Gemmules mem- branous, aspiculous. Colour —Nut-brown in the dried state. Habitat.—Coast of Scotland, Mr. Peach; Guernsey and Bantry Bay, Rev. A. M. Norman. Examined.—In the dried state. In the Johnstonian collection of British sponges in the British Museum there are four small specimens on one board, labelled Halichondria cinerea. Two of the speci- mens are upon a piece of card marked 17°, neither of which is the sponge described by Dr. Grant as Spongea cinerea ; the pieces are of different sizes, and represent two distinct undescribed species, the larger one being the type of our Isodictya Peachii. ‘his specimen is not in a very good state of preservation, but I have fortunately obtained others from Mr. Peach and the Rev. A. M. Norman in very fine condition. The reticulations of the dermal membrane are a very beautiful object ; they are three, four, and sometimes five sided, each side being the length of a single spiculum, but the regularity and beauty of the structure is frequently obscured by the occurrence of large patches of spicula, which are irregularly dispersed over the tissue. These additions to its structure appear to be more especially above those parts to which the skeleton beneath is more strongly adherent. The skeleton is more open and diffused in its structure than is usual in that of an Isodictya; the sides of the areas having two or three and sometimes more spicula in their length. The spicula of which it is com- posed are minute and very delicate in their proportions ; they are sub-fusiformi-acerate in form, of an average length of ast inch, and are ,7,,rd inch in diameter. These proportions, 278 A MONOGRAPH OF THE combined with the diffused structure of the skeleton, readily distinguish this species from others nearly allied to it in external characters. The gemmules are abundant immediately beneath the dermal membrane of the specimen from Bantry Bay ; they are round or oval, the mature ones are filled with minute globular vesicles, which presented no appearance of a nucleus or of granular matter within, the hight passing freely through their centres when viewed with a linear power of 660. ‘The average diameter of one of the largest gemmules was ;3;th inch in diameter, and of a perfectly globular vesicle within it ,4,th inch in diameter. I have dedicated this species to my friend Mr. Peach, a most ardent and disinterested lover of natural history, to whom I am indebted for many valuable specimens of British sponges. 3. IsopIcTYA PERMOLLIS, Bowerbank. HALicHONDRIA CINEREA, Johnston. Sponge. Encrusting, rarely massive. Surface smooth. Oscula simple or very slightly elevated. Pores in- conspicuous. Dermal membrane pellucid, aspiculous. Skeleton. Reticulations rarely more than unispicu- lous; spicula acerate, short and stout. Interstitial membranes. Tension spicula acerate, slender, few in number. Colour.—When dried, light yellow to nut-brown. Habitat.—Scarborough, Mr. Bean; Peterhead, Mr. Peach. Examined.—In the dried state. I first received this sponge from Mr. Bean, of Scar- borough, who pointed it out as probably a new species of Halichondria. ‘The general aspect of the species when washed and dried is somewhat like that of A. panicea when thinly spread over a stone or shell, but the surface BRITISH SPONGIADSA. 279 has not the slightest trace of the peculiar reticulated ap- pearance of that species, when examined with a lens of two inches focus. The specimens sent to me by Mr. Bean were thoroughly washed, and in that state they were of a light yellow colour, very fragile, readily compressible, and soft to the touch. I subsequently received two small specimens from Mr. Peach, which appeared to have been dried in the state in which they came from the sea, and these were of a nut-brown colour, well furnished with sarcode, and were consequently considerably more rigid and firm to the touch. ‘The reticulations of the skeleton are very distinct and regular; they are rarely wider or longer than the length of a single spiculum; the primary lines of the skeleton are most frequently unispicular, and the secondary ones, I believe, always so. The skeleton spicula are regularly acerate, and are short and stout in their pro- portions. A full-sized one measured ,th inch long. The dermal membrane in all the specimens I have examined was in so dilapidated a condition as scarcely to allow of my speaking with certainty on the subject of the specific cha- racters to be derived from it. On the board to which four specimens are attached, in the Johnstonian collection in the British Museum, and which are designated Halichon- dria cinerea, there are two on one piece of card; the smaller one is identical with our J. permollis. The mark on the card is 17°. 4, Isoptctya simuLo, Bowerbank. Sponge. Coating. Surface smooth, or rarely minutely hispid. Oscula simple, dispersed, large. Pores incon- spicuous. Dermal membrane pellucid, spiculous ; spicula acerate, slender, dispersed ; shorter than those of the skeleton, moderately abundant. Skeleton : primary lines bi- or trispiculous ; secondary lines uni- spiculous ; spicula sub-fusiformi acerate, short, and rather stout. Interstitial membranes, tension spicula, same as those of the dermal membrane; few in num- 280 A MONOGRAPH OF THE ber. Gemmules: spherical, membranous, aspicu- lous. Colour.—Fawn yellow. Habitat.—Bantry Bay, Rev. A. M. Norman. Ezamined.—In the dried state. The form of the type specimen of this species is that of an irregular patch, of an average diameter of two and a quarter inches, and, in the dried state, not exceeding two lines in thickness. The surface is slightly undulating, and appears smooth to the eye, and it is only when examined closely by the microscope that it is apparent that a few of the terminal spicula of the primary lines of the skeleton are occasionally projected beyond its plane. The oscula were about ten in number, and varied in diameter from half a line to the tenth part of an inch. The spicula of the dermal membrane are very little less in size than those of the skeleton. ‘They are irregularly, but evenly dispersed. In the interstitial membranes they are similar in size and form, but fewer in number. In the skeleton of this species the cementing keratode is in much greater quantity than I have observed in any other species of the genus with which I am acquainted, so much so as to frequently closely simulate the keratose fibre of a Chalina, but in no case have I seen it assume the decidedly cylindrical form that prevails in that genus. Imbedded in the sarcode immediately beneath the der- mal membrane, and in the other parts of the sponge, there were a considerable number of gemmules irregularly dis- persed. They were spherical in form, and the adult ones varied in diameter from ;2,th inch to ;4,th inch, and there were also numerous smaller ones in a more or less undeve- loped state. ‘The adult ones were all filled with well- defined, round or oval vesicular molecules. BRITISH SPONGIAD. 281 5. Isopictya vaRians, Bowerbank. HALICHONDRIA CINEREA, Johaston. Sponge. Encrusting. Surface smooth and even. Oscula simple, minute. Poresinconspicuous. Dermal mem- brane spiculous, reticulated ; rete unispicular ; spicula acerate, rather less in diameter than those of the skele- ton. Skeleton: reticulations unispiculous, rarely exceeding the length or width of one spiculum; spi- cula sub-fusiformi-acerate, short and stout; with a few short and stout acuate and cylindrical ones inter- mixed with them. Interstitial membranes. Spicula sub-fusiformi acerate, rather slender. Colour.—Light gray, in the dried state. Habitat.—Shetland, Mr. Barlee. Examined.—TIn the dried state. This sponge is in the Johnstonian collection of British Sponges in the British Museum. It is marked 17%, and labelled Halichondria cinerea, and is arranged on the same board with three other species of the genus Isodictya of this work. It surrounds two adjoining branches of a small Fucus, forming two parallel and united cylinders of sponge, an inch in length and seven lines in width, and varying in thickness from one to two lines. The dermal membrane is nearly entirely destroyed, but the reticulated structure with which it is furnished is in perfect preservation. The network is unispiculous, and the areas either four or five sided, rarely triangular, each side consisting of a single spiculum. ‘The skeleton is very regular in its structure ; the normal form of its spicula is sub-fusiformi-acerate ; with these there are frequently, but irregularly combined in its structure, the abnormal acuate and short stout cylindrical spicula; they occur in both the primary and secondary portions of the network, but more 282 A MONOGRAPH OF THE frequently in the latter than in the former position. Although tolerably abundant in the skeleton, I did not succeed in finding either of these forms in the reticular structure of the dermal membrane. The proportions of the sub-fusiformi-acerate spicula are as follows: length