oh 2 ‘3 a ‘ x iat rot > ea S Sangh BA eee SL Bey AS ; th Seay apnea Kaur oe ae ry oe ~ ites Se EY cabin diet) eu < us Gy, a Marre npetenoeiememetyn Se al a a ey . mf i ee I i i Si el pce Nia NO a 2 rh Pg ae ‘ ali phat, A Ae NT LTT Or Teng nreemonmeeanetas! (meee mre er: 8 TR e een ee OBO Or ESTE SO ern er RT a sepa a etree ate Octo FOR re schteihaenisMisiatiirets hog “ < ai 2 ae mre meneame recess sien cone raul AE roarreeorweitesnibattiee cee li eat Sie a SR ed Pace re tee nie a ars ere airtvan S RE T . a ena SPINE restr emet er mmmnernapen ia ie Pyne memo ldohwaege oT “i a a th Ree i ei ia ee ee eh oe ee ee Ped caro Sane aianead Tne eel SSR AGU OTE gta ee REUTER MO RN: AE ee NERS ES Bane mr, ee . eer cae a em ry $ met mey eervarenen heat TT np nt es "if Ho ROC DER tem Ne piesa nace ninemsn instr semaine sitemeter eacern ti AN emer rs pH Ape gee: ree ae i ee ee ar sc aga reeset EINE Ie Ra IN ame CNM penne Wee eo NEN AYS Cus =, Axa = #4 fi 7 Saye WY = 2S y= salva i S75 Sav N= 4 (William nlealey Del. ] =A Whe WIMIN Kf NAAR WANAWAY ©) 5 il hse | Fe Se. Oe es Division of Mollusks sectional Library . J J ‘ie ori os: % THE LAND AND FRESH-WATER SHELLS OF THE BRITISH ISLANDS. LONDON: Printed by SpotriswoopEk & Co. New-stieet Square. if 5 | MANUAL LAND AND FRESI-WATER SHELLS THE BRITISH ISLANDS. WITH FIGURES OF EACH OF THE KINDS. BY WILLIAM TURTON, M.D. NEW EDITION, WITH ADDITIONS, BY JOHN EDWARD GRAY, Ps.D., F-.RBS. F.L.S., F.R.G.S., V.P.Z.S. & ENT. SOC., ETC. LONDON: LONGMAN, BROWN, GREEN, LONGMANS, AND ROBERTS. The right of translation is reserved, FS a ea ‘* Nothing can be unworthy of being investigated by man, which was thought worthy of being created by God.” Boy.Let. *€ Divine communications are alike vouchsafed to us by the Volume of Nature and the pages of inspiration.’’ Bacon. “Deum sempiternum, omniscium, omnipotentem atergo transeuntem vidi et obstupui! Legi aliquot ejus vestigia per creata rerum, in quibus omnibus etiam minimis ut fere nullis que vis! quanta sapientia! quam inextricabilis perfectio !”’ Lin, Syst. Nat. p. 8. TO Moa Rt As EM A, MY HELPMATE IN ALL MY STUDIES AND ALL MY CARES, THIS LITTLE WORK IS Aredicated BY HER AFFECTIONATE HUSBAND, JOHN EDWARD GRAY. A 3 oe ip i oo fo ; 1. maximus, f. 4 a th || Ze 2. (Eulimax) flavus, f.15. 79 3. » agrestis, f. 6. . 80 | 47, 4. », arboreus moe 5. » | brunneus 82 | ag. 6. » tenellus 83 7.(Milax) Sowerbii, f.15. 83 | 49, Sone iss awates|:. 84 2. Cochleophora - . 85 | 50. * Vitrinina . Gh) |} ile 2. Vitrina - 5S 1. pellucida, f. 21, 87 | 52. ‘a 53. + Helicina . F 59 3. Zonites : - . 89 | 54, 1. alliarius, f. 39. . 90 2. cellarius, f. 40. . - 92 55. 8. purus, f. 43. . 95 4. nitidulus, f. 36. - 94 56. 5. radiatulus, f. 187. . 95 6. lucidus, f. 38. 96 Dille 7. excavatus, f. 39. 138. 97 8. crystallinus, f, 42. 98 | 58. 9: falvus,fj47- .. - 99 4. Helix . . 100 |) 3 1. (Acayvus) aspersa, 60 16 GP - 103 4 2: hortensis, 1b, Oe 106 3. hybrida, f.130. . 107 | 4. nemoralis, f. 23 108 5. (Pomatia) Pomatia, fos : 5 6. (Arianta) arbusto- rain, £26)" 115 | 62. 7. (Trigonostoma) ob- 63. voluta, f. 131. 116 8. (Chilotrema) — lapi- 64. cide, £51. i.) «Ak? | Joe 9. (Zurama) pulchella, 66. Peel Does . seats, 10. (Heliomanes) pisana, 1B OUh te . - 120 67. Page . (Heliomanes) fascio- lata, f 322 . (Heliom anes) virgata, irel5 . . 124 13. (Heliomanes) erice- torum, f. 37. Sle 14. (Hygromanes) can- tiana, f. 26. 128 15. (Hygromanes) car- thusiana, f. 27. 130 16. (Hygromanes) fusca, fAS6.) oe 5 - 182 17. (Hygromanes) rufes- cens, f. 28. 132 18. (Hygromanes) depi- lata, £135. . 154 19. (Hygromanes) gra- nulata, f. 29. 134 20. (Hygromanes) seri- cea, f, 184. 135 21. (Hygromanes) _his- pida, f. 41. . 136 22. (Hygromanes) con- cinna, f. 1385. Bu 7, 23. (Hygromanes) reve- lata, £183: - 139 24. (Hygromanes) acu- leata, f. 33. . 139 25. (Hygromanes) lamel- lata, f. 48. . . 140 26. (Delomphalus) ro- tundata, f. 44. - 141 27. (Delomphalus) pyg- mea, f. 46. = Ae aS 28. (Delomphalus) um- bilicata, f. 45. . 143 t7 Bulimina . 145 5. Succinea . - . 145 1. putris, fh 7d. . 146 2. oblonga, f. 139. . 148 6. Bulimus . 149 1. (na) montanus,f. 62. 150 2.5 4 obscurus; & 63. . Joi 3. (Elismia) acutus, f. 67. 153 7. Zua . 5 . 154 1. lubrica, f. 65. bo 68. 69, 85. 86. 87. 88. 89. CONTENTS. XV Page Page 8. Azeca 156 . ; ene : ’ 5. Limneade . 196 1. tridens, f. 52. od oe : 1. Limneus . 4 . 199 9. Achatina «= YS 90. 1. (Radix) auricularius, Iepaciculansta Gaus . 158 Looe. . . 201 10. Pupa . : 160 91. 2s pereger, f 6, Ue 101. 202 iB (Lauria) eylindracea 92. 3. stagnalis, f. 104. . 206 fer oe u _ GH 93. 4, (Stagnicola) palus- 2. anglica, f. 82. . 163 tris, f. 107. 208 3. (Pupilla) muscorum, 94, 5. truncatulus, f. 108. 210 Bay a. "464 | 95 6. glaber, f. 106. 211 4, (Abida) secale, 1 81. 165 2, Amphipeplea 212 1l. Vertigo 167 96. 1, glutinosa, f. 103. . 212 1. (Isthmia) edentula, 97. 2: inyoluta, fe 147. 214 f. 80. : a LG? 8. Ancylus 216 2. muscorum, f. 140. . 169 oe asrs 3. pyginea, f. 83. "170 98. 1. fluviatilis 219 4. alpestris, tig db 171 4. Velletia 92920 os substriata, f, 84. 5 Well 99. 1. lacustris, f. 196. 29] 6. antivertigo, f. 85. . 172 7. (Vertigo) pusilla, 5. Otina . - - 222 f. 86. aS) i) LOO: 1. otis < . 223 8. angustior, f. 142. . 174 6. Physa h 994 12. Balea . ‘ 2 5 101. 1. fontinalis, f. 110. 995 1, perversa, f. 70. - 176 7. Aplexus. _ 298 13. Clausilia ee lise 102. 1. hypnorum, f. 113. . 229 1. (Marpessa bidens, & ae. ) ‘ 182 8. Planorbis . . 230 2, (Iphigenia) biplieata, 103 ie (Coretus) corneus, 3. Rolph, eae 185 | 104. 2b (Gyraulus) | albus, 4, nigricans, f. 58, 59, f 97. . 234 io ae “ . 186 | 105. 3. glaber, f. 148. 235 106. 4, nautileus, f. 94. 236 107. 5. (Gyrorbis) carina- Me: tus, f. 89. 237 Seen aad 108. 6. complanatus, f. 87, 4. Auriculide . . 188 88. 90. . 240 109. 7. vortex, f. 91. 242 ec ie ea 190 | 110. 8. spirorbis, f. 98. 243 1. minimum, f. 77. 190) |) qa, 9. (Hippeutis) — fon- tanus, f. 93.. . 243 2. Conovulus 191 2 5 1. (Ovatella) denticula- ie 10, (Bathyomphalus) tas, £4, 5. 144: 192 contortus, f. 96. . 244 2 (Leuconia) bidenta- 9, Segmentina A . 245 tus, f. 145, 146 6 Mes) 113, 1. nitida, f. 99. . - 246 Xvi 114. 115. 116. LIE 118. 119. 120. 121. CONTENTS. Crass Il. CONCHIFERA. Orders and Sub-Orders of Page Ord. I. VENERACEA, 1. Cyclade . . 250 1. Cyclas ; = 250 1. rivicola, f. 1. = 252 2. cornea, f. 2. - 258 8. pallida . - » 254 4, pisidioides . . 255 5. lacustris > ee ait/ 2. Dreissenade. . 258 1. Dreissena . é - 259 1. polymorpha . . 260 Ord. III. Lastaczea . 263 3. Pisidiade . 5 PATE 1. Bisidium. =. 1. obtusale, f. 149, 2. nitidum, f. 150. . 265 to to former} ee fe 127. 128. 129. 130. Page ° . . 247 Page 8. pusillum, f. 7. - 266 4, pulchellum, f.151.. 266 5. Henslowianun, f. 6. 267 6. amnicum, f. 5. - 268 7. cinereum, f. 152. . 268, Cyrena . C 37269 Ord. IV. Untonacea . 270 4. Unionide 27 1. Anodon 2 1. cygneus, f. 8. - 2M 2. Alasmodon . . 276 1. margaritiferus, f. 9. 277 3. yee : 278 . pictorum, f 1k - 279 z tumidus, f. 13. . 279 A MANUAL OF THE LAND AND FRESH-WATER MOLLUSCA OF THE BRITISH ISLANDS. Mo.uuvsca is the name given to that large division of the animal kingdom which is characterised by having a soft fleshy body, destitute both of a bony skeleton supporting jointed limbs, and of a hard ringed skin. They are covered with a muscular coat, called a mantle, endued with a glairy humour, and are gene- rally furnished with a calcareous envelope called a shell, which is secreted by this coat for the protec- tion of the body or of the more vital organs of the animal. They are usually elongate, walking on a single central foot or disk, and are furnished with one or more pairs of organs on the head and sides. Their neryous system, which affords the most distinctive character of the larger groups of the animal king- dom, merely consists of a certain number of medul a B 2 SYSTEMATIC DISTRIBUTION. lary masses distributed to different parts of the body; one of the masses being placed over the cullet, and enveloping it like a collar. Linneus refers all the animals inhabiting shells to five different genera; viz., Limax, Ascidia, Anomia, Clio, and Sepia. ‘These genera may be regarded as the types of the classes proposed by Cuvier. Poli had, before his time, considered three of them as orders, under the names of Mollusca Reptantia, Subsilentia, and Brachiata. This division of the animal kingdom is subdivided into five classes in the following manner : — A. Crawling on a foot placed under the body. — Pedifera. I. GASTEROPODA, Gasteropods, or Univalves, which have a distinct head, furnished with eyes and tentacles, and are usually protected by a conical more or less spiral shell, often furnished with an operculum. II. ConcuireRA, Conchifers, or Bivalves, — Having the mouth placed between the gills, they and the body enclosed between the two leaves of the mantle, which are covered with two shelly valves united above by a ligament. B. Destitute of any foot. — Apoda. III. Bracnioropa, Brachiopods, or Lamp Shells. — Having the mouth placed at the base of two spirally twisted ciliated arms, between the two leaves of the mantle, which are co- SYSTEMATIC DISTRIBUTION. a vered with two separate shelly valves: they live attached to other marine bodies. IV. Preropopa or Pteropods, having a promi- nent head, with one or two pairs of fins on the sides of the neck, by means of which they swim about on the ocean; body is often covered with a thin glassy conoidal shell. VY. CepHALopPopa or Cephalopods, which have a large distinct head, furnished with eight or ten arms, by means of which they walk head downwards. The terrestrial and fluviatile Mollusca, of which alone we have to treat in this little work, are con- fined to the two first of these classes. The sHELL, which is peculiar to this division of the animal kingdom, may be seen covering the young animal in the egg, before it has gained all its organs, as was observed by Swammerdam, and verified by the more extended observations of Pfeiffer, Turpin, and others. This may easily be seen in the egg of the Limnei, Physe, Ancyli, and Bithinie, which have a transparent coat. The shells of the newly-hatched animals have been frequently considered as distinct species; and some very thin shells of land Mollusca, such as Vitrine, have been taken for the young of other well-known species, as H. hortensis. These young shells are easily known by their always being of a pale horn colour; the whorls are generally rather irregular, and enlarge very rapidly; and the apex of the whorl which was first formed is generally large B2 4 SYSTEMATIC DISTRIBUTION. and blunt, compared with the size of the shell. They are always destitute of colour, for the animal does not deposit the colouring matter until after it has been hatched ; and it is therefore generally easy to distinguish in the young shell (and sometimes also in the adult) that part of the top of the spire which formed the shell of the animal when in the egg. The shell is formed by the hardening of the animal matter, which is secreted by certain glands on the surface of the body, by means of chalky matter, also secreted by similar glands. It has been stated that the unhatched animal, very shortly after it is formed, begins to make its shell; and when it is hatched, deposits on the edge of the mouth of the little shell which covered its body in the egg, a small quantity of the mucous secretion. This dries, and is then lined with some mucous matter, intermixed with calcareous particles; and when this hardens, it again places on its edge another very thin layer of the mu- cous secretion, and again lines it as before. The mucous secretion first deposited forms the outer coat of the shell, which is called the pertostraca or epi- dermis, some persons haying regarded it as similar to the epidermis of the human skin. It is of use in protecting it from injury; while the mucous matter mixed with lime, which is placed within it, forms the substance of the shell itself, and consti- tutes, with the calcareous matter already existing, the crystalline structure of the shell. This depo- sition of mucus, and of mucus mixed with calcareous matter, goes on as the animal grows and feels the want of a larger shell for its protection: the shell is, SYSTEMATIC DISTRIBUTION. 5 in fact, moulded on the body of the animal itself, as the body grows; and for this reason any inequality in the body is moulded in the shell. The animal has the faculty, also, of mending any break or injury that its shell may have received, if it is not of such a magnitude as to derange all the func- tions of the animal itself; and it mends them in the same manner as it forms its shell, that is to say, by depositing first a coat of animal matter, and then lining it with mucous matter, mixed with chalk to harden it. But as the animal is usually very desirous of getting the repairs done as quickly as possible, and is most probably damaged by the injury it has received, these repairs are generally much more roughly executed than the shell itself, and com- monly destitute of regular colour. The particles which vary the colour of the surface of the shell are deposited, while the shell is being increased in size, immediately under the outer mu- cous coat; and as these particles are also secreted by peculiar glands, the colour is always situated in a particular manner on each species, the glands being gradually enlarged, and gradually separated, . but not changed in position, by the growth of the animal. All the variations exhibited in the colouring of the different species, or in the different individuals of the same species, are produced by the permanent or temporary interruption of the action of these glands. But for a more detailed account of these phenomena, I must refer the reader to my papers on the subject in the Philosophical Transactions for 1833, reprinted in Dr. Johnston’s Letters on Conchology. ; B3 6 SYSTEMATIC DISTRIBUTION. In describing shells, they should be regarded in their natural position; that is to say, in the way in which they are placed on the animal. Thus the part of the shell over the head of the animal is called the front, and that over the tail the back, of the shell; and the left and right sides of the shell correspond with the left and right sides of the animal. This is exceedingly easy to be determined in the univalve shells, because the apex of the shelly cone, whether it be simply conical or spiral, in all univalves (except Patella and Lottia) is over the hinder part of the animal; therefore, ifa shell is placed on its mouth, with the apex towards the spectator, the parts of the shell will correspond with the position of the person who is looking at it. As all shells are formed of a shelly cone (which, when very long, is generally rolled round an imagi- nary axis, for the purpose of diminishing the space that it occupies; but when it is short, is sometimes only slightly recurved, as in the Ancylus and Vel- letia), in order to maintain a similarity of terms for the same thing in these two forms, all the lines or grooves which pass from the apex of the cone to the mouth, and which are caused by some permanent modifications of the edge of the mantle, are called longitudinal or spiral, and all the lines which are paralled to the edge of the mouth of the shell, and which, in fact, are generally marks of its growth, or are caused by some periodical development of the margin of the mantle, are designated as concentric or transverse. ‘Thus the strie on the Cyclostoma elegans and Planorbis albus are longitudinal or spiral, SYSTEMATIC DISTRIBUTION. if and the lamelle on Helix lamellata and H. aculeata are concentric or transverse. But when we speak of the spiral shell as a whole, it is usual to call it short, or elongate, according to the length of the imaginary axis on which the whorls are rolled; and when we speak of the length of the mouth, it extends from the line which forms the front, to the hinder edge of the mouth, which, in the Ancylus, occupies the whole length of the shell: the breadth is the line which crosses this at a right angle. From the manner of formation, most spiral shells are liable to four kinds of distortion :— 1. The vertical elevation of the spire is more than normally depressed; the shells are called subdiscoidal or depressed. 2. The vertical elevation of the spire is more than usually elevated. When the whorls of these are continuous, these are called trochoid or subscalariform, and when they are separated from each other scalariform ; and when quite unrolled like a corkscrew, it is called ceratoid or cornucopia-shaped. 3. The whorls are irregularly twisted; this is most common in the genus Planorbis. 4, When the whorls are rolled in a contrary di- rection to that of the usual or normal direc- tion of the shell, they are said to be reversed ; when the mouth is on the left hand of the axis, they are sinistral; to the right, deztral. B 4 8 GASTEROPODA. It is equally easy to determine the natural position of the bivalves without the presence of the animal ; for the ligament is always placed on the dorsal sur- face of the animal, and the mouth is placed on that side of the apex of the valve, or wmbo, which is be- fore the ligament. Consequently, if a bivalve shell is placed on the table, with its hinge-side uppermost, and with the ligament towards the observer, the shell will be in its natural situation, and the sides of the shell will agree with the sides of the observer. It is to be remarked that Linnzus, and the natu- ralists of his school, described what is here called the front of the shell as the back, the left valve as the right, and vice versé ; and Lamarck in general (but not universally) followed the same rule. The me- thod above described is, however, so obviously cor- rect, and every other so liable to confusion from the want of a sound foundation, that it cannot fail, sooner or later, to be universally adopted. Crass I. GASTEROPODA. THE adult animal furnished with a more or less dis- tinct foot, placed under the body, for crawling on the ground or the surface of the water.. Having a distinct head furnished with eyes and tentacles, they are usually protected by one or by two unequal-sized valves, the largest being conical, spiral, and enclosing the greater part of the body, and the smaller forming GASTEROPODA. 9 a kind of lid or operculum to the aperture of the other valve. Sub-class I. Gill comblike, formed of one or two series of lamella, under the mantle on the back of the neck, or rarely round its edge, in an open gill cavity. Adult and larva shell- bearing ; larva furnished with deciduous cepha- lic fins. Unisexual or hermaphrodite, and self- impregnating : Ctenobranchiata. Order I. PEcTINIBRANCHIATA.— Gills comblike, formed of one (or rarely two) longitudinal series of lamin, or rarely of branched ves- sels, on the left side of the back of the mantle over the back of the neck. Animal unisexual; shell spiral. Order II. Scurrprancntata.—Gills consisting of two series of lamellae, forming one or two series over the back of the neck, or under the edge of the mantle round the foot. Ani- mal hermaphrodite, self-impregnating; shell conical, spiral, or symmetrical ; rectum often traversing the heart. Sub-class I. Respiratory organs variously formed, gills exposed, or only slightly covered by a fold of the mantle, or in the form of a closed lunglike cavity. Hermaphrodite, with reciprocal impregnation : Heterobranchiata. Order II]. PLEvRoBRANCHIATA.— Gills forming a tuft on the sides under a fold of the mantle. 10 GASTEROPODA. Shell spiral; adult and larva shell-bearing ; larva with deciduous cephalic fins. Order IV. GyMNOBRANCHIATA.— Gills exposed, or contractile into a cavity on the surface of the mantle. Adult shell-less; larva shell- bearing, with deciduous cephalic fins. Order V. PNEUMOBRANCHIATA.— Respiring free air in a closed chamber lined with pulmonic vessels, Adult and larva shell-bearing ; larva shaped like the parent, without cephalic fins. The last order consists almost entirely of terres- trial or fluviatile Mollusca, their organisation being only adapted for respiring free air; and there are a few fluviatile species found in the first and second order: the rest are all marine, and therefore ex- cluded from our consideration at present. The operculum of Gasteropodous Mollusca is like the shelly valve of those animals; and the shelly valve and the operculum together are homologous to the two valves of a conchiferous mollusk. I am therefore led to believe that the normal or typical form of mollusca is, to be protected by two valves or shells. If this theory be correct, the operculum should afford an important character for the distinc- tion of families and genera. As this theory is not generally understood, I may add that the operculum of these gasteropodous mol- lusca, like the shelly valve of those animals and of each of the valves of bivalves, — GASTEROPODA. 11 1. Is developed on the embryo long before it is hatched. 2. That it is placed on and covers a peculiar part of the body, which bears the same relation to it as the part of the body called the mantle, bears to the part usually called the shell of these animals; and it is formed, and increases in size, by an opercular man- tle in the same way as the shells are. 3. That the operculum is more or less conical, and is increased in size by the addition of new matter to the inner surface, and especially to the part of it near the margin, the new matter either forming more or less complete rings round the nucleus (or first- formed part )—when it is called annular, and is homo- logous to the simply conical shells, as the Patella ; or the new matter is deposited almost entirely on one edge of the nucleus, when the operculum forms a more or less elongated cone, which when long is generally twisted round an imaginary axis (like a spiral shell), the broad part of the cone being next the edge of the opercular mantle which generates the new matter for enlarging its size, as the mouth of the shell is on the outer edge of the mantle of the univalve shell. 4, That the operculum is attached to the animal by means of one or more muscles which, as in inequi- valved bivalved shells, pass from the larger valve, or shell, to the smaller one, or operculum. 5. The operculum as it increases in size is gra- dually moved on the end of the muscle; the many- whorled opercula of the ¢rochi revolve as many times on the end of the muscle as the many-whorled 12, GASTEROPODA. spiral shell turns on its imaginary axis, causing the muscles to move down the inner surface of the aperture. 6. The operculum is moulded on the opercular mantle, and is often lined internally with a shelly coat; and sometimes, as in certain shells, it has its outer surface covered with calcareous matter, de- posited by some special development of the oper- cular mantle destined for the purpose, as is the case with the cowries and some other shells. From these observations it appears that the oper- culum has all the characters of the appendage of the animal which has been usually considered as the shell of univalves, and the valves of bivalves. 7. That as the valves of bivalves are always twisted in opposite directions, so that each bivalve shell is composed of a dextral and sinistral valve united together by a ligament, so the operculum of a shell is always turned in the contrary direction to that of the shelly valve of the animal to which it be- longs, the dextral shell having a sinistral operculum, and vice versd. Thus the position of the nucleus of the annular operculum, or the spire of the spiral operculum, is always twisted in an opposite direction from that of the shell to which it belongs, as is the case with the two valves of a conchiferous animal. This is easily observed by comparing the position of the nucleus of the dextral and sinistral genera of Ampullaride, or the spiral operculum of a sinis- tral malformation of a gasteropod, with that of one of the normal form. I may observe that, as is the case with spiral shells, when the shell is turned GASTEROPODA. 13 in an abnormal direction, the direction of the oper- culum is also changed. 9. The opercula are repaired, when injured or partly broken off, in the same manner and by the same means, and when repaired offer the same ex- ternal appearance, which shells do under similar cir- cumstances. See Ann. and Mag. N. H. 1850, v. 476.; and 1854, xiii. 419.: The principal difference between the operculum and the valves or shells of the gasteropod con- sists — 1. In the operculum having no cavity. The cone of which it is formed is either very much depressed, so as to be nearly flat or even concave, as in the annular or subannular operculum, or very much compressed, forming only a spiral band, as in the spiral operculum. The absence of a cavity is a difference only of degree, for the valves of some gasteropods (as Umbrella, for instance) are so flat as to produce no cavity, and thus greatly resemble the annular operculum of Ampullaria, and the flat valves of some Calytre are like the subspiral operculum of Littorina, but the greatest resemblance is to be ob- served in the small flat valves of some Gryphea, Exogyra, Chama, and other genera of bivalve shells, which are attached by one of their valves. ‘These valves are often quite as flat and destitute of any cavity as the operculum of any gasteropod; and it is to be remarked that these valves exactly resemble a spiral operculum in shape, the remains of the liga- ment forming a spiral mark on the outer surface, showing how the valve has rotated on the body of 14 PECTINIBRANCHIATA. the animal, as the operculum rotates on the foot of the gasteropods. 2. The operculum of by far the greater number of gasteropods is only formed of animal matter, so that the operculum appears to consist entirely of what constitutes the periostraca or drap marin of the shelly valves; but the shells of some gasteropods, as that of Aplysia, Bulla, of some land mollusks, and the valves of some bivalves, as Lingula, have only a very thin shelly internal layer, strengthening the thick perios- traca; while many opercula, like the generality of shells, have a shelly coat deposited on the inner side of the horny periostracal coat, and others have both the inner and outer surface of the animal or perios- tracal part, covered with a shelly coat like the lining. OrvEeR I. PECTINIBRANCHIATA. GiLus comb-like, formed of one, or rarely two lon- gitudinal series of lamelle, or very rarely some branched vessels, on the left side of the mantle, over the back of the neck; the gill cavity is open, the mantle edge being free for the back of the neck. Animal unisexual; shell spiral; operculum usually well developed, rarely absent. This order is divided into three sub-orders, thus :— I. Toxrrera.— Head small; proboscis retractile, under the base of the tentacles; teeth elon- ROSTRIFERA. ~ 15 gate, subulate, implanted in the fleshy pro- boscis. Carnivorous, venomous, marine. Il. Prososcipirera. — Head small; proboscis retractile under the base of the tentacles; teeth variable, in three, five, or one longitu- dinal series, on an elongated cartilaginous tongue membrane. Carnivorous, marine. III. Rostrrrrera.— Head produced into a ros- trum, with the tentacles on the side of its base; teeth in seven longitudinal series, on a cartilaginous tongue membrane. Phytopha- gous, marine, fluviatile, and terrestrial. The two first sub-orders are confined to marine animals; the last contains a few fluviatile or terres- trial species. Sub-order III. RosTrRIFERA. Head moderate, with a more or less elongated, produced, contractile, transversely-annulated ros- trum; tentacles subulate, far apart, on the sides of the base of the rostrum; eyes on the outer side, or behind the base of the tentacles; teeth on an elon- gated linear lingual membrane partially received in the visceral cavity, in seven longitudinal series; the central and inner lateral teeth fixed, with a broad base; the two outer lateral teeth versatile, suberect, the upper edge lobed. Phytophagous, marine, flu- viatile, and terrestrial. This group is divided into sections, according to the form of the foot, which is modified by the 16 ROSTRIFERA. habits of the animals: — 1. Platypoda. The foot depressed, expanded for crawling. 2. Protopoda. Foot roundish, truncate, or clavate when the ani- mals are sedentary, living in shells attached to marine bodies. 3. Leptopoda, Foot compressed for leaping. 4. Heteropoda. The foot compressed, fin- like, with a small sucker for attaching itself to float- ing bodies. The British fluviatile and terrestrial species all belong to the first section, and form a division of it, characterised by having the eyes sessile, or nearly so, on the outer side of the bases of the subulate tentacles, and the mantle enclosed in the shell, which have been called Edriophthalma, Cochlea. These animals are divided into groups or families, according to the formation of the respiratory organs or gills, and position of the eyes, thus :— 1. Cyclostomide. Kyes lateral, external; gills vascular, 2. Littorinide. HKyes lateral, external; gills lami- nal ; operculum spiral. 3. Bithiniade. Kyes lateral, external; gills lami- nar; operculum annular. 4, Viviparide. Eyes lateral, external ; gills f- lamentous ; operculum annular. 5. Valvatide. yes lateral, external; gills sub- pinnate, exposed ; operculum spiral. 6. Aciculide. Eyes at the internal base of the tentacles ; operculum spiral. CYCLOSTOMID&. ba Fam. 1. CYCLOSTOMID A, The gills are vascular, branched, lining the inside of the mantle, the outer edge of which is free from the back of the neck; the eyes are sessile, on the outer side of the base of the tentacles; male organs hidden in the hinder part of the cavity under the edge of the mantle. Mantle with a thin edge. Jaw none; vent on the right side of the edge of the mantle. Foot broad, body central spiral, enveloped in a simple edged mantle, which is covered with an ovate spiral shell, with a roundish mouth, and fur- nished with a spiral operculum. Fig. 1. Cyclostoma elegans. d, showing the under side of the foot, divided into two parts. e, operculum. These animals live on vegetable matter, like the snails, and are found in damp places on a chalky soil. Cc 18 CYCLOSTOMIDZ. The Cyclostomide differ from the true Pneuwmono- branchiata, with which they have been generally previously confounded, in the mantle being free from the back of the neck, leaving the pulmonary cavity open, and in the animals being unisexual and provided with a distinct well-developed spiral oper- culum. M. Moquin Tandon observes that in the front of the pulmonary cavity of Cyclostoma elegans, near the collar, the pulmonary vessels are closer together, pro- ducing some parallel slightly flexuous ridges, which appear to be rudimentary gills. (See pp. 74. 166.) These animals, when they walk, apply their pro- boscis to the ground to assist them in progression. 1, CycLostoma. (Circle Shell.) Shell ovate-spiral; mouth simple, united all round; operculum of a few flat whorls, with a simple shelly internal coat; the foot divided into two parts by a longitudinal central groove. (See fig. 4. p. 17. Operculum rather ovate, double- edged, internally concamerated, with transverse concentric and septa. Shelly whorls 4 or 5, gradually increasing. Nucleus excentric. The foot is formed of two longitudinal portions: as the animal walks, the portion on one side is first advanced, while the animal holds on by the other; and then holds on with the advanced portion as the other side is gradually advanced before it. (See p- 17. f. 4. Rossmdsler, Icon. i. 89. t. 2. f. 80. 82.) This is the case with Cyclostoma lineolata and the CYCLOSTOMA. 19 exotic species with ovate, few-whorled opercula. The foot of the species with orbicular, horny, many- whorled opercula is not so divided, but broad and expanded, like the foot of other terrestrial Mollusca. Dr. Turton, in his descriptions of this genus (ed. 1. 93.), says the shell has no epidermis; but this is a mistake: indeed, I am not aware of any shell that is really destitute of this important covering (see Pail. Trans. 1833), though it varies greatly in thickness in different genera, and in this genus it is very thin ; but in some Indian species of the family it is thick, and forms a decided brown coat. In the same manner, he describes the operculum as horny. It is, as in most of the European species to which I am inclined to restrict the genus, decidedly shelly. The generic name is from the circular circum- ference of the aperture or mouth. 1. 1. CycLostoma elegans. Elegant Circle Shell. — Shell conic-oval, with raised spiral striz, and the peritreme attached at its upper part. (t. 7. Bi 45>)) Cyclostoma elegans. Drap. p. 32. t. 1. f. 5. 8.; Brard, p. 103. “t. 3. f.7.8.; Linn. Trans. xvi. f. 63.; Turton, Man. ed. 1. 93, f. 75. ; Leach, Syn. Moll. 203.; Forbes and Hanley, B. M., iv. 201. t. 122. f. 3.— Cyclostoma (Ericia) elegans. Mog. Tand., Moil. Franc. ii. 496. t. 37. f. 2. 23.— Junior Cyel. Saputus. Maduyt, Moll. Vien. 79. — Cyclostomus elegans. De Montfort, ii. p. 287.— Turbo elegans. Mont. p. 342. t. 22. f. 7.; Linn. Trans. viii. 167. — Turbo striatus. Da Costa, p. 86. t. 5. f.9.— Turbo tumidus. Penn. B. Zool. 128. t. 82. f. 110. — Nerita elegans. Wiiller, Verm. 11. 177.— Var. Smaller, and nearly Smooth. — Cyclostoma marmorea. Brown, Edinb. Journ. Nat. and Geog. Sci.,13.t. 1.f. 10. 11. In hedges and under stones, in chalk and lime- Cc 2 20 LITTORINIDZ. stone districts; England and Wales (Lister), 8 Scot- land, Edinburgh. Animal grey-brown. Shell half an inch long, and four-tenths of an inch wide, solid, grey or purplish-yellow, mostly purple at the tip, often marked with two rows of purplish brown spots; spire composed of five rounded volu- tions, marked with numerous close-set raised spiral strie and finer longitudinal ones between them; aperture round with a smalt angle at top, and an um- bilicus behind the pillar; operculum hard, horny ex- ternally, and marked with a single depressed spiral line, from which some very fine striz radiate towards the circumference. Lister (Jab. Anat. iv. f. 1. 2. 3.) gives some ac- count of the anatomy ; and a very detailed description has lately been published by the Rev. Mr. Berkeley (Zool. Journ. iv. 278.). The tips of the tentacles have a bright brown spot very visible to the naked eye, which Montague considered as a second eye. It is the organ of smell. The tentacles, in repose, are annulated, resting on the sides of the trunk. Brard describes two unequally compressed carti- laginous pieces, one on each side of the buccal cavity. They are rounded on one side, thin and sinuous on the other; slightly tubercular and whitish. Fam. 2. LITTORINIDA. Trunk produced and wrinkled, not retractile; ten- tacles far apart, on the side of the head; eyes ASSIMINIA. 21 sessile, on the outer side of the base of the ten- tacles; jaws horny; teeth in 7 longitudinal series, converging. Mantle-edge simple. Gill single, formed of very numerous flat free cross-folds, occupying nearly the whole of the inner sur- face of the cavity. Foot moderately broad for walking. Opercular lobe simple. Operculum spiral, horny, of gradually enlarging whorls. Amphibious; marine, or in brackish water. 1. AssimintA Leach MS. (Assiminia.) Shell ovate, conical, solid; mouth ovate; tentacles simple, very short, scarcely longer than the tu- bercles on which the eyes are placed, and united to their side; operculum horny, ovate, of a few rapidly enlarging whorls. (p. 23. f. 3.) The animal differs from Littorina in the apparent position of the eyes, which is an anomaly among the water or Ptenobranchous Mollusca. This animal was first indicated, and its peculiari- ties pointed out, in my paper above quoted, inl 321 when I made the following remarks on its structure. * The animal of this shell differs from all others of the order (to which it belongs), by the eyes appear- ing to be placed at the end of the tentacle; but I believe that they are placed on a peduncle as long as the tentacle, and the peduncles and tentacula are soldered together.” Mr. Berkeley, in his description of the animal (Zool. Journ. v. 429.), observes,—‘* The most re- markable circumstance in this animal is the position c 3 22 LITTORINIDA. of the eyes at the tip of the tentacle, as in Helix and its allies, and not at the base. It would appear as if there were in reality no tentacula, and only the tubercle, common to many Mollusca, at the base of the tentacula, a little more developed than usual.” I am inclined to retain my former theory; for if the pedicle of the eye of this genus is minutely examined, it will appear to be formed of two parts united by a suture. There has been a great controversy about this genus. Consult Ann. and Mag. Nat. Hist. 1855, Xvi. pp. 114. 184. 272. and 422.; 1836, xvi. 49. 56. A shell which I described from India, under the name of Turbo Francesia (Wood, Supp. t. 6. f. 28.), has been found by Mr. Benson to have the same kind of animal, and to be a second species of the genus. The central tooth is wider below, the base trun- Fig. 2 cated in the middle, prominent on both sides ; produced into a horn, cutting edge triangular, with five or seven pointed lobes. The first la- teral tooth with seven lobes, the third lobe larger ; the second slender, upper part claw-like, serrated on the outside; the third tooth rounded at the tip, ciliate, denticulate (fig. 2.). Teeth of Assiminia. a, central; 6, e, d, lateral teeth, 2, 1, ASsIMINIA Grayana. Liver-coloured Assiminia. — Shell ovate, acute, solid, liver-brown; suture slightly impressed; mouth ovate. (f 127.) ASSIMINIA. 23 Nerita Syncera hepatica. Gray, Med. Repos. 1821, p. 239. — Assiminia Grayana, Leach, MS.1816; Flem. B.A. 275.5 Berkeley, Zool. Journ. v. 429. t. 19. f. 4.; Leach, Syn. Moil. 155. t. 9. f. 4. 5.3 Gray, Ann. and Mag. N.H. xvi. 183. 422, xviii. 49.; Forbes and Hanley, B.M. ii. 70. t. 71. f. 3, 4. t. H. H. f. 6.; Clark, Ann. and Mag. N. H., xvi. 114. 272. 1855, xvii. 57. 1856. — Lymneus Grayanus. Jeffreys, Linn. Trans. xvi. 378.— Paludina Grayana. Potiez and Mich, Gal. i. 251. +. 25. f. 23, 24. Inhab. the mouths of rivers, and small streams connected with them, seldom out of the reach of brackish water. Foot broadly obovate, obtuse, compressed, evi- dently of two distinct laminz, the lower \, Projecting beyond the upper, and sepa- rated from it by an accurately defined line; above fuscous, beneath olivaceous, shaded with cinereous; tentacles very short and obtuse, fuscous, eyes at their tips; muzzle porrect, not truly probos- cidiform, deeply notched in front, fus- cous, strongly annulated; the edge of the lips paler: on each side is a groove running backwards from the base of the tentacula. Shell about + inch long, ovate, solid, bright, shining, liver-brown, with a conical spire, and slightly impressed suture. The axis is imperforated. Oper- culum horny, ovate, black-brown. Very like the small Littorine, but more solid, and differs in the animal; it is curious that so abundant a shell should have been overlooked by Montagu and his correspondents. There may be noticed two marine species, some- times found with the former. c4 Assiminia. a and ec, head. 24 BITHINIADZ. 1. LITTORINA anatina. Paludina anatina. Drap., Michaud, Alder, Mag. Zool. and Bot. ii. 116. — Bithynia inflata. Leach, Syn. Moll. 210. Sometimes found in the marshes at Greenwich, with the Assiminia Grayana. ‘The shell is ovate, perforated, thin, transparent; the whorls are ven- tricose, rounded, and the mouth ovate; the operculum is horny, brown. It is like Bithinia ventricosa, but smaller and shorter, and has a horny spiral opercu- lum, like the periwinkle; the peristome is continued ; the shell is often covered with green Alge. 2. LITTORINA muriatica, Turbo muriaticus, Linn. — Cyclostoma acutum, Drap. which has been placed by the latter author as a fresh-water species, is abundant on many parts of our coasts. It is nearly allied to Littorina ulve. Hart- mann has formed a genus called Hydrobia from these small Littorine. Fam. 3. BITHINIADZ. Head annulated, contractile, narrow, and not ex- tending to the plane of the foot. Teeth in 7 longitudinal series, the lateral. converging. (Moquin, t. 39. f. 26. 28.) Jaws none. Ten- tacles subulate, equal. [yes sessile, on the outside of the base of the tentacles. Mantle simple in front; neck with small veil on the right side. Gills single, in the form of a trans- verse parallel, flexuous plaits attached to the BITHINIA. 25 inner surface of the respiratory cavity; the ridges narrow, slightly dilated, and angulated near the middle. (Moguin Tandon, t. 39. f. 31. 32.) Stomach with cartilaginous stylets. Male organs at the hinder base of the right tentacle, always exposed, filiform, bifid. (Moguin Tan- don, t. 39. f. 37.) Shell spiral; mouth oval, entire; peristome thickened. Operculum an- nular, with an internal shelly coat; crabby claws, not withdrawn in the aperture of the shell. Oviparous, eggs in oblong masses. 1. Brrarnia Gray. (Bithinia.) Operculum filling the mouth of the shell, lined internally with a thick shelly coat; nucleus subcentral (f.4.c.); the mouth of the shell ovate, continued, rather angular behind, with a slightly thickened internal rib. Fig. 4. These animals are ; é ; f 2 J oviparous, their eggs : = being deposited in oblong groups, like Bithinia ventricosa. the Limnei or Pond Ose ene Snails, on the stems and leaves of fresh-water plants. (See Pfeiffer, Moll. t. 6. £.10, 11, 12.) M. Moquin Tandon erroneously considers the Hy- drobia of Hartmann, which has a subspiral horny operculum, as a sub-genus of Bithinia, under the name of Bythinella, and gives the name Elona to the true Bithinie. 26 BITHINIADA. 3. 1. Birninta tentaculata. Tentacled Bithinia. -—— Shell oval-oblong, yellowish horn-colour, smooth, semitransparent, with five rather flat volutions, and without umbilicus. (t. 10. f. 120.) Helix tentaculata. Linn. Fauna Suec. 531. (List. Ang. t. 2. f. 19.); Gmel. 3662.; Mont. 389.— Bulimus tentaculatus. Poiret, 61.—Lymnea tentaculata. F'lem. Ed. Ency. vii. 78. — Nerita jaculata. MWiiller, Verm. ii. 185. — Bithinia jaculator. Leach, Syn. Moll. 209.; Risso, Eur. M. iv. 100. — Bithinia tentaculata. Gray, Man. 93. t. 10. f. 120.; Forbes and Hanley, B. M. iii. 14. t. 71. f. 5.6. t. H. . f. 3.— Turbo Janitor. Vall. Exer. H.N.6.— Turbo nucleus. Da Costa, t. 5. f. 12.— Paludina tentaculata. Flem. B. A. 315.— Paludina impura, Lam. vi. 175. (List. Conch. t. 132. f. 32.) ; Brard, 183. t. 7. f. 2.; Turton, Man. 134 f. 120. — Cyclo- stoma impurum. Drap. 36. t. 1. £.19.; Sturm, Fauna, t. vi. 8% Ile Young. — Turbo levis (?). Walker, f. 38. — Nerita spherica. Miiller. Var. 1. Shorter, less, and more conical. Drap. t. I. f. 20. In ditches and canals; common all over Britain. Animal blackish, with golden dots; foot two- lobed in front, narrow and subacute behind; ten- tacle setaceous, long; the eyes black. Shell half an inch long, and three-tenths wide, often covered with a blackish foul coat; spire com- posed of five volutions, the first very tumid, the others hardly raised; pillar without umbilicus. 4. 2. BITHINIA ventricosa. Ventricose Bithinia. —Shell conic, yellowish horn-colour, smooth, semi-transparent, with five very tumid volu- tions, and a small oblique umbilicus. (t. 10. f. 121.) Bithinia ventricosa. Gray, M. Rep. 1821, p.239.; Man. 94. — Turbo Leachii. Sheppard, Linn. Trans. xiv. 152, 1822.— BITHINIA. 27 Bithynia Leachii. Leach, Syn. Moll. 209; Forbes and Hanley, B. M. iii. 16. t. 71. f. 78. t. HH. f. 1. — Paludina Trochelliana. Philippe. — Paludina Kickxii. Vestend, Bull. Acad. Brux. 1835, 375.— Paludina decipiens. Mich. Mag. Zool. 1843, 2. t. 64. f. 2. — Paludina Michaudi. Duv. in Rev. Geol. 1845, 211. — Bithinia Kickxii and B. Michaudi. Dupuy, Moll. — Paludina acuta. Fleming. Br. Anim. 315.— Cyclostoma simile. Drap. 31. t. 4. f. 15. (?) —Paludina ventricosa. “ Leach, MSS.;” Sheppard, Brown, Brit. Shells, t. 41. f. 74, 75. — Paludina humilis. N. Boubée, Cat. —Paludina similis. Twrton, Man. 135. f. 121. Alder, Mag. Zool. and Bot. ii. 116. In ditches and canals; often even where the water is slightly brackish ; south of England. (Gray, 1821.) Shell a quarter of an inch long, and two lines broad, with four or five very tumid volutions; aper- ture dilated, nearly circular, projecting more out- wardly, or out of the line of the columnar axis, with a small umbilicus behind it. The fry, or mass of egg, of this species, are dis- posed on a tough strap-shaped green membrane, in a double row, consisting of six or seven pairs placed opposite to each other; and this elongated receptacle is fixed to the under surface of aquatic plants. Mr. Sheppard received it from Dr. Leach, under my name, but he changed it to Turbo Leachit. I do not think it is C. simile of Draparnaud: in Dr. Turton’s figure the volutions are scarcely sufficiently ventricose. The shell is often covered with a ferruginous in- crustation, and the apex of the spire is sometimes eroded. Mr. Alder observes (Mag. Zool. and Bot. ii. 116.), “The Paludina viridis of Turton’s Manual (ed. 1. 28 VIVIPARID®. 135, f. 122.) I take to be the young of P. simils (Bithinia ventricosa), judging from specimens in Mr. Clark’s cabinet.” Most probably this idea is correct, as I have not been able to find any authority for Draparnaud’s species being found in this coun- try; and it is to be remarked that Turton’s account is taken from Draparnaud, and Dr. Turton does not give any habitat for the species. M. N. Boubée’s specimen of Pal. viridis proves it to be a /ydrobia or minute Littorina: it has a horny subspiral oper- culum. Mr. Alder also thinks that the Paludina stagno- ‘rum Turton, Man. (ed. 1. 136. f. 123.) may probably be a mere slender variety of this species. (Mag. Zool. and Bot. 1. 116.) I think it is much more probably a Littorina, as he considers it the same as Paludina acuta of Drap. In the absence of speci- mens, it is impossible to decide; and, as Dr. Turton does not give any locality, it is even doubtful if the whole account of the species and figures were not derived from Draparnaud’s work. If intended for any British species, it must be Littorina ventricosa, which is common in the ditches with Cardium edule, &c. near Tilbury Fort. Fam. 4. VIVIPARID/. Head annulated, contractile, broad, extended to the plane of the foot. Teeth in 7 longitudinal series; the lateral broad, ovate, converging. Jaws 2, lateral, horny, narrow, sharp-edged, PALUDINA. 29 smooth, resembling the lateral jaws of Lymnea (Moquin, t. 40. f. 5.), and advance horizon- tally one against the other. Tentacles coni- eal, cylindrical, blunt, and unequal; the right larger, swollen at the base. Eyes on short tubercles, on the outer side of the base of the tentacles. Mantle simple in front; neck with a small lobe on each side. Gills single, formed of three series of flat filaments, and forming an oblique line down the left side of the branchial cavity, and bent at the end. (Mogquin, 76. t. 40. f. 2. 12. 13.) The foot ovate, much dilated, extended before the muffle, and with an anterior groove. Male organ inclosed in the swollen base of the right tentacle. Viviparous. Shell spiral-ovate, covered with a hard olive periostraca. Aperture ovate; peristome simple. Operculum ovate, annular; nucleus sublateral, horny, without any shell-coat. 1. Patupina Lam. (Marsh Shell.) Operculum horny, the nucleus rather on the inner side; shell conoid or oblong; mouth roundish, slightly angular behind; peristome united all round, thin. They are called Paludine from their being found in marshes and ditches. The animals are viviparous, the young being hatched while the eggs are in the oviduct of the mother. The shells of the newly-hatched individuals are covered with spiral bands of cilia. 30 VIVIPARIDZ. : Fig. 5. The lingual band is strong, slender, Man lsh diy | i elongate ; teeth la- ae a wl NWapan l minar, longitudinal, Wf ins HAWS /f ‘ Li Hy \ iy M WH subovate, apex re- curved, the mid- dle lobed, and ob- tusely toothed on each side; the la- Paludina erystallina. teral teeth nearly simi- b, operculum. lar, slightly curved, api- cal edge denticulated on each side; the inner shorter and broader, the outer teeth winged on the outer edge (fig. 6.). a= Teeth of Paludina vivipara. a, central; 6, c, d, lateral teeth. 5. 1. Patupina crystallina. Crystalline Marsh Shell. — Shell thin, oval, acute, volutions five, much inflated, with three brown bands; the suture deeply impressed; spire blunt mucro- nate. (t. 10. f. 118.) Helix vivipara. Schret Flusse, 330.t. 8. f. 2—Cochlea vivipara. Da Costa, B. C.81.t.6. f.2.—Helix vivipara.— List. Ang. t.2. f.17.; Petiv. Mus, 84. n. 814.; Donovan, B.S. iii. t. Sis PALUDINA. 31 Montagu, T. B. 386. — Paludina erystallina. Gray, Med. Rep. 1821, p. 239.— Paludina Listeri. Forbes and Hanley, B. M.iii.8. t. 71. f. 16.—Cyclostoma achatinum. Drap. Moll. 36. t. 1. f. 18.— Paludina achatina. Sow. Gen. f. 2.— Palu- dina contecta. Mog. Tand. Moll. F. ii. 512. t. 40. f. 1.24. — Vivipara communis. Dupuy, Moll. Franc. 537. t. 27. f.5.— Natica vivipara. Ferussui.— Cyclostoma contectum. AZil. Moll. Maine and Loir. 5. 1813.— Nerita fasciata. Miiller Verm. ii. 182. part. — Nerita vivipara. Miiller, 11. 182. — Cyclostoma viviparum. Drap. 34. t.1. f.16, 17.— Paludina vivipara. Lam. vi. 173.; Nilson, 88.; Turton, Man. ed. 1. 133. f 118.; Brard, 174. t. 7. f. 1.3; Rossm. f. 66.; Desh. viii. 511. — Viviparus fluviorum. De Montf. ii. 247.— Paludina achatina. Sow. Gen. f. 1.; Leach, Syn. Moll. 208. In still waters and slow rivers far from the sea. Shell an inch and a quarter long, and an inch broad, thin, transparent, finely striate longitudinally, of an olive colour, with three brown bands on the larger volution; spire composed of five inflated and deeply divided volutions, the last very large, the first a mere point; aperture pear-shaped, slightly pro- duced at the upper angle; the inner lip a little re- flected so as to half-close the umbilicus. The young shells are subglobose, pellucid, obscurely banded, rather flattened above, and furnished with five ciliated lines. 6.2, PALUDINA vivipara. Common Marsh Shell. — Shell rather thin, conic-oval, acute; volutions six, rather tumid, with three olive-brown bands ; the sutures well-defined. (t. 10. 119.) Helix vivipara. Linn. Faun. Gall. ii. 529, S. N. part. 1247.— He- lix ventricosa. Oliv. Ad. 178.—Helix fasciata. Gmelin, SN. 364. b.— Helix ventricosa. Olive, Zadoral. 178.—Paludina vul- 32 VIVIPARIDA. garis. Gray, Med. Rep. 1821, p. 239. ; Leach, Syn. Moll. 207. —Paludina fasciata. Desh., Lam. vii. 513.— Nerita fasciata. Miiller, Verm. 182.— Cyclostoma achatinum. Drap. 36. t.1. f. 18.— Turbo achatinus. Sheppard, Linn. Trans. xiv. 125. t. 1. f. 18. — Paludina achatina. Brug. E.M. t. 458. f.1.; Lam. HT, vii. 174.; Rossm. 109. f. 66*.; Turton, Man. 133. f. 119. — Helix vivipara b. Gmelin. SS. N. 36. 46.— Nerita fasciata. Sturm. Faun. vi, 2. t. 12.—Cochlea vivipara. Da Costa B. C. 71. t. 6. f. 2.—Vivipara fluviorum. De Montf. 246.— Limneza vivipara. lem. E. Ency. vii. 77.—Paludina vivipara. Say, Amer. Conch. t. 10; Forbes and Hanley, Brot. Moll. iii. 11. t. 71. f. 14.15. t. H. H. f. 2. — Vivipara fasciata. Dupuy. Moll. Franc. 540. t. 27. f. 8. Young shell with numerous hairy bands: Helix compactilis. Pulteney, Col. Dorset. 48. Very young shell: Vitrina femorata. Auctor. Inhabits the upper parts of rivers, where the water is not brackish. Shell resembling the last, but of a more oblong shape, with six volutions, which are not so much swollen, and consequently the sutures are not so deep. The young shells are furnished with numerous close ciliated spiral lines. Lister gives the anatomy of the former species, and Cuvier of this (t. 6. f. 1. 4.), in the Mém. Mollusques. Though Lister has figured the two species as found in Britain, they had been confounded by English conchologists until I noticed them in the Medical Repository for 1821, when I also pointed out that they were known to Lister, and that the young shell of the two species offered the very different characters noticed in their descriptions. They are sometimes found together in the same river, as at Uxbridge, Middlesex. Messrs. Forbes and Hanley have changed the name which I gaye to the new species, because the VALVATIDZ. 33 species was “not characterised:” overlooking the fact that I pointed out the very marked difference between them found in the young shell; thus firmly establishing the distinction which some concholo- gists had only considered as a sexual peculiarity, the most ventricose being the female. Fam. 5. VALVATID&. Rostrum annulated, elongate, bifid. Tentacles equal, elongate, tapering, rather blunt; eyes on a small tubercle on the inner side of their base. Jaws, two, lateral, narrow, approaching each other above, where there is a third rudimentary jaw, like a small tubercle. (Moquin, 32. t. 41. f. 6.) Mantle-edge thin, with a tentacle-like appendix on the right side, which has been called the branchial thread. Vent on the right side, under the mantle. Gulls plumose, exserted when the animal is expanded, formed of an oblong, tapering, conical process, furnished on each side with a series of spirally-twisted laminz, placed opposite to each other. (f. 9.6.) Foot truncated, nicked slightly, and produced at each angle in front, rounded behind. The male organ is like a third tentacle, situated behind the base of the right tentacle; the orifice of the female organ is under the collar on the right side of the vent. (Moguin, t. 41. f. 5.) ** Hermaphrodite ;” oviparous; eggs emitted singly; fluviatile, eating aquatic plants; rarely D 34 VALVATIDZ. swimming. Shell conical, thin, covered with an olive periostraca; mouth round, with a con- tinued simple peristome. Operculum horny, suborbicular, formed of many gradually enlarg- ing whorls, which have a raised membranaceous outer edge, forming a spiral ridge on the outer surface (f. 9. d.). The shells are known from Paludinz by the shelly cone being circular, and not bent in in any part by the proximate whorls. 1, VatvaTa Muller. (Valve Shell.) Shell with the spire a little elevated, or flat and disk- like; aperture quite circular, united all round, and furnished with a horny operculum marked with a single raised spiral membranaceous line. So named from the valve or lid which covers the orifice of the aperture. 7. 1. VALVATA piscinalis. Stream Valve-shell.— Shell globular, with an elevated obtuse spire, and a deep central umbilicus. (t. 10. f. 114.). The lingual plate of V. piscinalis is elongate; Fig. 7. the central tooth sub- quadrate, base pro- duced on both sides, incurved, cutting edge triangular, the middle cusp with a pectinated lobe on each side ; late- ral teeth somewhat similar, laminaceous, toothed on Teeth of Valvata. a, central ; 6, c,d, lateral. VALVATA. 35 each side; the apical denticules larger than the rest. (Fig. 7.) Nerita piscinalis. Jiiller, 172.— Trochus cristatus. Schroet, Fluss-conch. 280, t. 6. f. 11.— Valvata obtusa. Brard, p. 190. t. 6. f. 17.; Turton, Man. ed. 1. 130.; Pfeiffer, 198. t. 4. f. 32. t. 1. f. 13.— Valvata fontinalis. Leach, Syn. Moll. 206.— Turbo cristata. Poir. Prod. 29. — Nerita obtusa. Studer, Coxe’s Travels, iii. 436. — Cyclostoma obtusum. Drap. p. 33. t. 1. f. 14.— Turbo fontinalis. Mont. p. 348. t. 22. f.4.— Turbo thermalis. Dillwyn, p. 852. — Helix piscinalis. G'mel. 3627.—- Valvata piscinalis. Lam. vi. 172. ; Kenyon, Mag. N. Hist. ii. 425. f. b. c. d.; Alder, Mag. Zool. and Bot. ii. 116.— Lymnea fontinalis. Flem., Ed. Ency. vii. 78, — Nerita pusilla. Miiller, Verm. 171. Young rather depressed, umbilicus rather wider, — Helix fascicularis. Gmelin, S. N. 3641.; Alten Syst. 74.t. 8. f. 16.— Valvata depressa. Pfeiffer, D. Moll. J. 100. t.4.f.33,—Val- vata minuta. Drap. Hist. Moll. 42. t. 1. f. 36. 38. — Val- vata Moquiniana. Dupuy, Moll. Franc. 586. t. 28. f. 15. In canals and ponds; common to all parts of England. Animal whitish; trunk grey, rugose. Shell nearly a quarter of an inch long and as much broad, globular, thin, ight horn-colour, very finely spiral-striate, and marked with some obscure con- centric lines; spire of four volutions, tumid, and deeply defined, and having much the appearance of a Trochus, with a deep central umbilicus; opercu- lum dull greyish white. Varieties: —1. Shell high, um- Fig. 8. bilical; cavity small. 2. Shell de- pressed, umbilicus deep ; also varying much in size, some specimens being three or four times as large in the adult age as others. Some continental naturalists, overlooking the fact D2 36 VALVATIDA. that all conoid shells are more depressed in their young state, have, from the peculiarity of their forma- tion, regarded the young as a distinct species under the name of Valvata depressa. (See f. 8. a. b. c.) The animal and operculum are well described by Montagu (Test. Brit. 351.), who justly compared the animal to that of the next species, though in his arrangement one shell isa Zurbo and the other a Helir ; but he saw the difficulty of this arrange- ment. See his note at p. 367., and also at p. 461., where he describes the animal of V. cristata. gs. 2. VALVATA cristata. Crested Valve Shell.—Shell discoid, flat above, and umbilicate beneath; whorls 3. (t. 10. f. 115.) Valvata cristata. Gray, Man. 98; Miiller, Verm.198.; Alder, Mag. Zool. and Bot. ii. 116.; Forbes and Hanley, B.M. iii. 20. t. 71. f. 11. 12, 13.— Valvata spirorbis. Drap. p. 41. t. 1. f. 32, 33. ; Brard, p. 187. t. 6. f. 15, 16. ; Turton, Man. ed. 1.131. f. 115.— Valvata Miilleri. Leach, Syn. Moll. 205. Nerita valvata. Gmel. 3675.— Helix cristata. Mont. p. 46. ; Vign. 1. f. 7, 8.—Planorbis cristatus. Flem. Ed. Ency. vii. 69.— Trochus cristatus. Maton and Racket, Linn. Trans. vill. 167.—Turbo cristatus. ZYurton, Dict. p. 227.—Valvata planorbis. Moll. 42.; Drap. Tab. 41. t. 1. f. 34, 35.; Tur- ton, Man. ed. 1. 132. f. 116. (?) — Valvata pulchella. Studer, Core’s Trav. iii. 436.— Valvata branchialis. Gruithuisen, Nov. Act. Nat. Cur. x. 1821, 437. t. 38. f. 13.— Junior. Val- vata minuta. Drap. 42. t. 1. f. 36—38.; Turton, Man. ed. 1. £117: In ditches and canals, on aquatic plants. Shell about the tenth of an inch in diameter, pale horn-colour, striate transversely, with three volu- tions; the upper surface a little sunk, the under side umbilicate, so as to expose the interior volutions. VALVATA. of Mr. Alder observes (Mag. Zool. and Bot. ii. 117.), ** Dr. Turton has introduced two other species, V. planorbis Drap. (f. 116.), and V. minuta Drap. (f. 117.), into his Manual, but no specimens of them are now to be found in his cabinet.” Mr. Alder says he took some pains to Fig. 9. investigate these two species 6) when in Paris, on examining three of the principal collec- / -\ » tions there; those of the Jar- \— eZ din des Plantes, the Baron ~ a de Férussac, and the Duc deg, animal; &, gill; Rivoli. ‘In the latter only, c, operculum. I found any thing under the name of V. pla- norbis. ‘The specimens (which were originally La- marck’s) were V. cristata Miiller. M. de Férussac had specimens, under the name of V. minuta, from two different individuals. Those from M. Pfeiffer are, I think, the young of V. cristata, and the others (1 forget from whom, but with the name of Dra- parnaud) the young of V. piscinalis. Mr. Miller in- troduced V. minuta into his catalogue of the land and freshwater shells of the environs of Bristol, but no specimen of it is preserved in the Bristol Museum. Dr. Turton says that his V. minuta is the Helix serpuloides of Montagu. This is well known to be a marine shell, referrible to the genus Skenea of Fleming. Mr. Thompson of Belfast has, however, favoured me,” continues Mr. Alder, “ with the ex- amination of a shell which may possibly turn out to be the V. minuta Drap., though I suspect it to be marine.” D3 38 ACICULID&. Dr. Gruithuisen describes the operculum as formed of concentric rings: this is very pardon- able, as it is very easy to overlook its spiral cha- racter. Fam. 6. ACICULID. Muzzle annulated, produced. Tentacles subulate, not swollen at the end. Eyes large, on the back of the neck, rather behind, and between the base of the tentacles (fig. 10.). Gills vascular; jaws none. Foot oblong; divided across in the mid- dle. Male organ large, at the hinder part of the base of the right tentacles, exserted like a third tentacle. Shell spiral, sub-turreted ; aper- ture oblong; peristome simple; outer lip rather dilated, sinuous. Operculum horny, spiral, of few rapidly enlarging whorls. Terrestrial, unisexual. On account of the shape of the shell, the animals have been placed with Bulimi. When the animal was first discovered it was then arranged with Auriculide, on account of the position of the eyes. But M. Férussac (Dict. Class. H. N. ii. 90.), in 1822, first noticed the operculum ; and it has been more lately described by Mr. Alder, the Abbé Dupuy, and others. The animal is very rapid and irritable, but comes out of the shell with great hesitation. It carries the shell horizontally when it walks. Preferring dampness, it hides itself from the sun, secreting ACICULA. 39 abundance of very clear aqueous mucus. It often leaves half the foot exposed when all the other parts are withdrawn. 1. ACICULA. Shell subcylindrical, with a blunt tip; mouth ovate, simple, outer lip simple, thin, slightly reflexed over the pillar, forming a slight perforation. Ani- mal with two long contractile slender vg. 10. tentacles, between which and the \y, eyes, at their hinder base, are two My jagged blackish spots (fig. 10.). Dr. Turton (Manual, ed. 1. p. 83.) appears to have considered the spot at the base of the tentacles as the rudiment of a lower pair. Dr. Hartmann (Sturm, Fauna, t. 1. f. 4.) describes the tentacles as retractile; but he uses the same term to describe the tentacles of Cyclostoma and Carychium, which agree with these in only being contractile, and not retractile like those of Helices, and other land Mol- lusca. This genus, on account of the similarity of its shell, has been confounded also with Truncatella of Risso, which is a marine animal, provided with gills and a distinct operculum. The animal walks with its shell nearly perpen- dicular, twisting it round in a very odd manner, and then letting it suddenly fall again. 9. 1. AcIcuLA fusca. Brown Acme.— Shell cylin- drical, obtuse, glossy brown, transparent, with D4 40 ACICULIDA. rather distant parallel oblique longitudinal strie. (t. 6. f. 66.) Helix Cochlea. Studer, Coxe’s Travels, 430.—Auricella lineata. Jurine, Helv. Aln. 187. 33. — Acmea lineata. Hartm. Sys. Gast. 1821, 49.—Turbo fuscus. Boys and Walker, Test. Min. Rar. 12. t. 2. f.42.; Montag. Z. B. 330.; Wood, Supp. t. 6. f. 15.— Auricula lineata. Drap. Hist. 57. t. 3. f. 20, 21.—Carychium cochlea. Studer, Catal. 21.— Carychium lineatum. Férussac, Tab. Syst. 100.; Rossm. v. 54. t. 28. f. 408. — Cyclostoma lineatum. Férussac, Dict. Class. H. Nat. ii. 90. — Pupula lineata. Charp. Moll. 8. 22. — Carychium acicularis. Fér. Dict. S. N. vii. 188. 1817.— Acicula lineata. Hartm. N. alpina. 215, 1821.— Acicula fusca. Pfeiffer, ° Pneum, iii.; Gray, Cat. Cyclophoride, B. M. 68.— Acme lineata. Hartm. in Sturm, Fauna, vi. t. 2. 1828. ; Alder, Trans. ii. 338.— Acme fusca. Gray, Man. 223. t. 6. f. 66. ; Forbes, Brit. Moll. t. 125. f. 7.— Acme minuta. Brown, H, C.t. 14. f. 26. (?); Forbes and Hanley, B. M. 204. — Truncatella lineata. Hart. Gast. t. 1. — Carychium fuscum. Fleming, B. A. 270.; Jeffreys, Linn. Trans. xvi. 364. — Bulimus lineatus. Drap. Tabl. 67.; Turton, Man. ed. 1. 82. f. 66. Inhab. on moss and Jungermannie, in damp places, springs, &c. Shell the tenth of an inch long, of a cylindrical form, and hardly decreasing in diameter for its whole length, highly polished and marked with rather re- mote regular longitudinal strie, which are hardly distinguishable without a good glass; spire composed of six very slightly raised but well-defined volutions, the two terminal ones of which are smaller and paler; aperture roundish-oval, with the margin thin, and a little reflected at the pillar, where it forms a slight perforation. The animal and shell are sometimes dark brown and at others pale yellowish white. They are some- times found reversed. SCUTIBRANCHIATA. 41 M. Moquin Tandon, who is not addicted to di- viding species with too great minuteness, divides these shells into four species, and separates them into two sub-genera; I have not been able to verify the accuracy of the subdivision. 1. AURICELLA. Shell with elevated ridges. Aper- ture sinuous, slit obliquely in the front part im a line with the suture. A. (Auricella) lineata, t. 38. f. 4—7.— Shell red- dish yellow, with distant ridges, whorls rather de- pressed; aperture with a short oblique slit; the peristome sub-continuous. (Auricula lineata. Drap. Hist. t. 3. £. 2021.) The shell is sometimes nearly smooth. 2. Puatyia. Shell smooth, aperture flat, without any slit in the upper part. A. (platyla) fusca, t. 38. f. 8. 16.— Shell very smooth, reddish yellow; whorls slightly convex, peristome nearly continued. (Turbo fuscus. Walker, T. M. Rar. 112. f. 42. — Aurychium lineatum. Ross. Jun. f. 408.) OrvER Il. SCUTIBRANCHIAT A. GILLS consisting of two series of lamellae, forming one or two series over the back of the neck, or under the edge of the mantle round the foot; rec- tum often traversing the heart. Animal herma- 42 NERITIDZ. phrodite, self-impregnating (?). Shell spiral, or conical, symmetrical. With the single exception of Neritina and Proser- pina, all the animals of the sub-order are marine. Fam. 1. NERITID. Muzzle very short, annulated, provided with a hood ; jaws two, one above and the other below, both toothed on the edge. Tentacle contractile, subu- late, pointed. Eyes on short pedicles at the base Fig. 11. Neritina fluviatilis. a, foot below; 6, head above; c, operculum inside. of the tentacles (fig. 11.6.). Tongue membrane broad, with very numerous series of transparent glass-like teeth ; the central teeth (fig. 12.) very Fig. 12. Teeth of Neritina fluviatilis. a, central. unequal; the second and fifth on each side large, broad, dark-coloured; the lateral teeth NERITINA. 43 very numerous, sub-similar, very slender, curved at the top; the inner one on each side largest. Body and shell spiral. Gill single, formed of small leaves placed symmetrically one against the other, and forming a transverse mass on the back under the mantle. Sides of the foot with- out any membranaceous fringe, with beards on its upper surface. Foot oblong, shorter than the shell, circular, truncated behind. ji, 13, Shell hemispherical, flat beneath; spire lateral ; inner lip flattened, transverse; outer arched ; inner surface not pearly. Operculum with a process on the inner side under the nucleus, forming acini a kind of hinge with the edge of the /uwatilis. inner lip of the shell. (Fig. 13.) The peculiar structure of the operculum makes this family more closely resemble the bivalve shells: the processes appear to answer the same purpose (that of keeping the two parts in their proper situa- tion) as the teeth of the hinges in the bivalves. In the exotic genus Navicella, which, on account of its large mouth, has been confounded with the Patelle, the processes occupy the greater part of the operculum. There is only a single fluviatile genus of this family found in Britain. 1. Neritina Lam. (Neritine.) Shell half-ovate, thin; inner lip slightly toothed; operculum only slightly calcareous, and fur- 44 NERITIDA. nished with a sharp flexible outer edge; foot short, rounded at each end. This genus is separated from the marine Nerita by the pillar being sharp, only slightly denticulated, and the outer lip not being toothed within. Neritina is the diminutive of Nerita, the ancient name of a sea-shell. The greater part of the species are confined to freshwater streams, but one of the North American species is found for 200 miles up a river, from the mouth where it is quite salt, to beyond the reach of the tide, where the water is perfectly fresh. One species (Neritina viridis) is only found in the sea. (See Phil. Trans. 1835.) They live on vegetable substances, crawl slowly, and have not been ob- served to swim on the surface of the water. They deposit their eggs on the surface of their shells; these are roundish, and provided with a thick opaque coriaceous case; and when the animal hatches, the upper part separates from the lower by a circular slit, like the lid of a box, the base remaining adherent to the shell. M. Deshayes and several other conchologists, es- pecially those who only study the external form of shells, have proposed to unite this genus to the Nerites, because some of the species are marine, and some of the fluviatile species have a tooth on the pular lip. The genera are, however, very distinct ; and they may be well characterised by the structure of the operculum. (See Phil. Trans. 1833, p. 814.) The operculum of the Neritine is solid, shelly, and furnished with a thin flexible outer edge; that of NERITINA. 45 the Nerites is horny, covered on both sides with a hard shelly coat. The position of the horny oper- culum is shown by a groove in the edge between the two coats; and if a knife is inserted, the coats can be separated from the operculum. As the periostraca is essential to the structure of the shell, and is always present, some shells being formed of scarcely any thing else, so it is with the operculum, the horny part similar to the periostraca of shells being always present, and forming its es- sential part, and a shelly coat being in some in- stances added to the outer surface, as in Turbo and Phasianella, or to the inner surface, as in this genus, in which the horny part is very thin and scarcely visible, except where the shelly coat is very thin, as at the flexible edge. These animals absorb the septa which separate the whorls of the spire, when they have arrived at their full size, so as to allow more room for the spiral body, without increasing the size of the shell; and this can be done without endangering the strength of the shell, as only a very small part of the whorl is exposed on the surface. A similar absorption is to be observed in many Auriculide, and to a less extent in the Cones, where the septa are only reduced in thickness. (See Phil. Trans. 1833, p. 798.) This absorption is only superficial, and produced by that portion of the surface of the mantle which lies close to it, and is not to be confounded with the absorption of the bones of vertebrated animals, where it is produced by vessels which ramify in the sub- stance of the bone, and which are accompanied by 46 NERITIDA. other vessels to replace with new portions the part which has been removed. The apices of the spires of these shells are some- times eroded; those are more so which live in stag- nant or nearly stagnant waters. The late Mr. Sowerby (Min. Conch. iv. 49.) supposed that this was produced by “some acid developed during the fermentation of vegetable matter in marshes or at the bottoms of the rivers.” Others, who were not aware how the animals walked, have said that this erosion of the apex was produced by the animal rubbing it against the ground in progression; ex- plaining also the erosion of the umbones of the Uniones in the same manner. Dr. Shuttleworth believes that the erosion of the apex of some of the fluviatile Neritine is caused by the animal’s filing off the apices by its teeth, the mark of the teeth being left on the surface of the erosion. This is particularly the case with the specimens which live in streams in granitic coun- tries. And he suspects the animals supply them- selves with the calcareous matter to form their shell from this source, the body of the Neritine being withdrawn from the top of the shell as the shell is enlarged in size. 10. 1. NERITINA fluviatilis. River Neritine. — Shell convex, dilated, tessellate, with variously co- loured spots; spire short, lateral. (t. 10. f. 124.) Neritina fluviatilis. Lamarck, vi. ii. p. 188.; Flem. B. A.321. ; Turton, Man, ed. 1. 138.— Neritina europea. Leach, Syn. Moll. 181. — Nerita fluviatilis. Linn. S. Nat. 1253. ; Miiller, NERITINA. 47 ii. 194.; Drap. p. 31. t.1.f.1—14.; Brard, p. 194. t. 7. f. 9.10. 12.; Mont. p. 470.; Turt. Dict. 127.; Forbes and Hanley, B. M. iii. 3. t. 71. f. 1. 2. t. H. H. f. 1. — Nerita fontinalis, Brard, Coq. Par. 196. t. 7. f. 11. — Neritina zebrina, N. peloponnensis. N. numidica, N. Mittreana. Recluz. — Neritina intexta. Villa.— Neritina Sardon and N. trifasciata. Menke.— Neritina Hildreichii. Schwerz. — Nerita Bourguignati. Recluz, Jour. Conch. 1825, 293. —Nerita Prevostiana. Pfeiffer, D. Moll. ii. 49. t. 8. f. 11, 12.— Nerita thermalis. Boubee in Bull, 1833, 12.— Theo- doxus lutetianus. De Montfort, ii. p. 351. — Neritina fontinalis. Brard, Hist. C. 196. t. 7. f. 11. 18.; Pet. Gaz. t. 91. f. 3.; List. Conch. ii. 1. 38.; Swamm. B. N. 80. t. 10. f. 2.— Neritina dalmatica. Sow. C. Illus. f.57.— Neritina variabilis. Hecart. Moll. Vail. 1. 146. In slow rivers, adhering to stones. Animal white ; head and back of the neck blackish ; hinder part of the foot sometimes black spotted ; ten- tacle long, white, with blackish line. Shell about three eighths of an inch long, and two broad, convex above and flat underneath, obscurely striate transversely, of a greenish or whitish colour, variously chequered with spots or bands of white, brown, purple, or pink; spire consisting of three volutions, the first very large, oblong, and oblique, the others small and lateral; aperture horizontal, semielliptic, with the margin sharp and entire; pillar white, transverse, sloping down to a sharp edge, and quite entire; operculum semilunar, yellowish, with an orange border, and underneath is a strong raised grooved spire at one end. The shells are often covered with calcareous in- crustations, deposited by the water, which make them look like pieces of dirt, and thus escape being seized on by the fish. The continental conchologists have described se- 48 PNEUMONOBRANCHIATA. veral species allied to the above. Rossmiisler reduces them to three; but, from the specimens which I have received under different names, I greatly doubt if they are more than mere local varieties of our species. Nilson found a small variety or species in Sweden, on the shores of the Baltic, with Mytilus edulis, Cardium, &c. Our species has been found in similar situations in Loch Stennis, Orkney, by Mr. Edward Forbes. OrpverR V. PNEUMONOBRANCHIATA. THE respiratory organs consisting of a number of pulmonary vessels spread over a closed bag-like cavity on the back of the neck. The edge of the mantle adherent to the back of the neck of the animal, forming a closed pulmonary chamber, leaving only a hole for the entrance and exit of the air, which is closed by an external valve on the side of the cavity. They breathe free air, and either live constantly on the land or in the water, in which latter case they come periodically to the surface to respire. The larve are shell-bearing, shaped like the adult, and destitute of any cephalic fins. The lingual membranes are furnished with numerous longitudinal series of similar, sub-equal, teeth. The shell is rarely wanting. They are all destitute of any operculum, but close the shell, during the torpidity of the animal (pro- duced by either dryness or cold), with a lid or epi- PNEUMONOBRANCHIATA. 49 phragm formed of its inspissated humours, and some- times hardened with a little caleareous matter. These animals are all hermaphrodite, but require mutual impregnation, and feed on vegetables; but some few have carnivorous propensities, and others, when thev live near man, acquire bad habits, and eat paper and dead animal matter. They may be divided into groups, according to the structure of the mouth, and the form of their tentacles, which conform to their more or less aquatic habits. This order is divided into four sub-orders, in the following manner : — I. PETROPHILA.— Eyes at the end of an elongated contractile peduncle; tentacles flat, contractile ; jaws none; organs of generation far apart, apertures united by a lateral groove ; teeth flat, four-sided, close, side by side; shell none, as Onchidiade. II. Gropnita.— Eyes at the end of an elongated retractile peduncle; tentacle cylindrical, re- tractile, sometimes wanting; organs of gene- ration in a common cavity; operculum none. Terrestrial. 1, Lumbricivora.— Mouth proboscis-like; jaws none; teeth slender, conical, distant. Carni- vorous, subterraneous, as Testacellide. 2. Phyllivora.— Mouth prominent; jaws one or two, distinct ; teeth four-sided, flat, with a re- curved tip, close together, side by side; her- bivorous, as Arionide and Helicide. E 00 ONCHIDIADA. III. Liwnopniia. — Eyes sessile; tentacles two, subeylindrical, or depressed, simply contractile ; jaws two, or three, distinct; teeth numerous, flat, with a recurved tip; orifices of generation separate, but near; operculum none, as Auri- culide and Limniade. IV. THALAssopHiLa.—LEyes sessile, on the back of the frontal disk, formed of the united expanded tentacles; jaws distinct; teeth numerous, flat, close, side by side; operculum none, or distinct. Marine. Sub-order I. PETROPHILA. Eyes at the end of an elongated contractile pe- duncle; tentacles flat, contractile; organs of gene- ration far apart, apertures united by a lateral groove; jaws none; teeth numerous, four-sided, flat, close together, side by side*; shell none. Fluviatile, or marine. Fam. 1. ONCHIDIADZ. Body ovate or oblong, mantle, covering the whole of the back, edging the foot, convex, more or less tubercular; tentacles and eye peduncles con- tractile; aperture of respiration on the hinder * The teeth described as those of Peronia Mauritiana in the Annal. and Mag. of Nat. Hist., Nov. 1853, were those of Testa- cellus, which had been sent to me wrongly named. See Ann. and Mag. N. H., Jan, 1854. ONCHIDIUM. 51 part of the groove between the mantle and the foot; foot narrowed; shell none. On rocks near the sea covered with the tides. 1. ONCHIDIUM. Animal oblong; mantle completely covering the back, convex, coriaceous, tuberculated; eyes two, at the end of cylindrical retractile pe- duncles; tentacles none, or in the form of rounded oral lobes or a buccal veil; jaws none, tongue denticulated ; orifice of reproductive organs widely separated; pulmonary cavity be- hind the heart, with the aperture posterior, between mantle and foot. 11. 1. ONCHIDIUM celticum.— Oblong mantle thick, coriaceous, rather shining, covered with short thick rounded tubercles, surrounded with smaller ones ; foot oblong. Onchidium celticum. Cuvier (?); Couch; Forbes and Hanley, he Bh te WO aie Tnhab. Cornwall, on rock at West Comb in Sand- level Bay (J. Couch). The edge of the mantle considerably exceeds the foot; the under side of this edge minutely granulated; foot pale yellowish. “‘ Jaws none; tongue broad, and furnished with upwards of seventy transverse rows of blunt slightly curved teeth, each row containing 108 teeth, and divided by a minute central tooth of a triangular form bearing a single blunt spine. The reproductive organs are in the same individual. The male organ is E 2 52 TESTACELLIDA. placed at the right side of the head, while the other parts are situated at the posterior extremity of the body; they are nevertheless connected by a long slender duct buried in the muscles at the side of the foot ; the vent is distinct from the lung.”—Hancock. Sub-order Il. Gz0pPHILA. Eyes at the apex of elongated cylindrical pe- duncles; tentacles cylindrical, shorter, and lower down than the eye peduncle, sometimes very small or wanting; the two orifices of the organs of ge- neration confounded in the same external orifice ; operculum none. ‘Terrestrial. Sub-division 1. Lumbricivora.— Mouth proboscis- shaped; jaws none; teeth numerous, slender, conical, pinlike, distant (fig. 14.); head, tentacles, SSW SW if ~ SS \\ a fi ( Wiitts SSW WOM YL Teeth of Testacellus haliotideus. and eye peduncle retractile under the skin. Car- nivorous, worm-eating. Fam. 2. TESTACELLIDZ. Foot without any subcaudal gland; teeth slender; TESTACELLUS. 53 the eyes rather below the acute tip of the eye peduncle. The only English genus of this family has the shell and spiral body of the animal very slightly developed. In Helicophanta it is more developed, like a Vitrina or Streptaxis; and in Oleacina it is sufficiently large to allow the animal to contract into it as in Helix and Achatina, with which they hitherto have been confounded. * Body with two longitudinal grooves ; lips cylindri- cal, retractile. (Testacellina. ) 1. TesTaceLuus. (Testacelle.) Body elongate, tapering in front, with two diverging grooves from the front of the mantle, extending to the head; mantle small, covered with an ear- shaped shell, with a very short spire, which is placed on the hinder part of the body. The mouth of the shell is very large, the outer lip thin, with a slight notch at the hinder end. Shell ear-shaped, on the hinder part of the body (figs. 15, 16.). a, Testacellus haliotideus, walking, expanded. b, shell elevated from end of body. E 3 54 TESTACELLIDA. Faure Biguet, who first discovered the animal, called it Testacellus; Draparnaud and Cuvier have changed the name to Testacella. The animals, according to the observations of M. Férussac, have a peculiar mantle (or rather ap- pendage of the mantle), which is simply gelatinous, contractile, and habitually hidden under the shell, divided into several lobes, and susceptible of an extraordinary development, so as to envelope the whole of the contracted body of the animal, and thus protect it from extreme drought. The animals live for the greater part of their life in holes under ground, only coming to the surface to change their locality; and they remain buried during the cold or very dry weather. It is this power of protecting themselves from the effect of sudden changes of temperature, there is little doubt, that has allowed them to adapt themselves with such facility to our climate. They deposit their eggs under ground; these are oblong, large and covered with a thick elastic coat, and burst when put into a warm place. 7 12, 1. TESTACELLUS haliotideus. Tar-shaped Tes- tacelle-—Shell roundish-oval, with the outer lip dilated, and the pillar flat and broad, and scarcely reflected outwardly. The lateral grooves of the body close together in the front of the shell. Tongue with 20 longitudinal series of teeth. (t. 3. fig, 19, 20.) Testacellus haliotideus. Faure, Big. Bul. Soc. Phil. 1802, 98.; Férussac, Hist. t. 8. f. 5. 9 ; Sowerby, Gen. f. 1, 2.; Mog. TESTACELLUS. 55 Tand. Moll. Franc. ii. 39. t.5.— Testacella haliotidea. Drap. t. 8. fig. 44, 45.; Forbes and Hanley, B. M. iv. 26. t. GGG. f. 1.— Testacella scutulum. Sow. Gen. f. 3.3.; F. D. Mag. N. Hist. vii. 229.f. 41. ; Lukis, Mag. N. H. vii. 224. f. 29. — Testacella europxa. Roissy. Buff. v. 252 — Testacellus europeus. Montf. C. S. ii. 95. fig. — Testacella Gallic. Ohen, Lehrb. N. iii. 212. t. 9. f. 8. 1815. — Testacellus Medii Templi. Tapping, Zoologist, xiv. 1856, 5099. — Testacella Companyonii. Dupuy. Moll. Frane. i. 47. t. 1. f. 3.— Testa- cellus bisuleatus. Risso, Hur. Mer. iv. 58.— Testacella bisulcata. Dupuy.1. c. 44. t. 1. f. 2. Inhab. France. The “ Coquillade” was recorded as living near Dieppe by M. Dugul, in 1740. Na- turalised in gardens. Animal yellowish, reddish, or grey, sometimes spotted on the sides beneath; tentacles cylindrical. The shell is broad in proportion to its length, and the pillar, near the upper end, is broad and nearly flat. This animal is common in the island of Guernsey, Testacellus haliotideus. c, head retracted when depositing the eggs. where it was first observed in the garden of Mr. Lukis, in 1801. The late Mr. Sowerby afterwards E4 56 PHYLLIVORA. found it in a garden at Lambeth. When the animal deposits its eggs, the head and tentacles are drawn in. See fig. 16. a, 6, c, from Mag. Nat. Hist. vii. 226. f. 39., exhibiting the animal in its different positions. In winter, they bury themselves from one to two feet deep in the earth, and are most above the sur- face from August to November. They chiefly live on worms, and sometimes will attack slugs and smaller specimens of their own species; shells of their own kind being sometimes found in their stomach. The Testacella scutulum of Sowerby and Testa- cellus Medii Templi of Mr. Tapping are very slight varieties of the common species. Testacellus Mangei has a more developed shell, the lateral grooves far apart in front of the shell, and only 15 longitudinal series of teeth on the tongue. Sub-division 2. Phyllivora.— Mouth simple; jaws distinct, horny; teeth numerous, four-sided, close together, side by side, with a reflexed toothed apex; head tentacle and eye peduncles retractile under the skin. Eyes at the apex of the club of the peduncle. Herbivorous. The following account, of the teeth is abridged from an elaborate paper by Mr. William Thompson in Ann. and Mag. N. Hist. 51. 86.; from which also the figures are taken : — “The tongue of the Phyllivora, generally, is a thin expansible membrane, two thirds or three PHYLLIVORA. vn fourths of which is rolled into a tube, fig. 17. ¢; the posterior end of this tube is closed, its anterior ex- tremity expanded into a flat- Fig. 17. tened or spoon-shaped form, which plays against the edge of the horny upper jaw, fig. 17. a, thus acting more in the capa- city of an under jaw than a Mouth mass of Helix. true tongue.” “Tt is enclosed in the muscular head of the animal, and is connected with the cesophagus, f. 17. b, at the anterior end of the tube, the extended upper portion of the cwsophagus forming the roof of the mouth, while the expanded surface of the tongue covers the lower part of the mouth. The head is usually globu- lar or nearly so, sometimes slightly attenuated back- wards. From the junction of the tube of the ceso- phagus and tongue, the former passes backwards through the head, and leaves it at its upper part behind (sometimes coming out almost at the top of the head), while the tongue takes at once a downward and backward direction, and protrudes its closed end distinctly at the lower part of the head. “Tf the tubular part of the tongue be laid open and expanded (when it always proves of the same width as the naturally expanded portion), it will be found to be covered on its upper surface with a vast number of plates, each carrying one or more tubercles which do not stand perpendicularly to the * Lister and Adanson regarded the hard lingual membrane of Zima and Helix as a second or lower jaw. Adanson men- tions the teeth, and compared the “ jaw” to an étrille. Swam- ‘merdam called the tongue a cartilage. 58 PHYLLIVORA. surface of the plates, but are abruptly curved pos- teriorly, so that the apices of the projection inva- riably point towards the closed end of the tongue, f.19.and 20. These teeth are distributed in rows all over the membrane, and are closely packed together. The longitudinal rows always consist of straight lines, but the transverse rows are variously curved, often bow-shaped, sometimes angular, rarely straight (figs18:). Fig. 18. a éb Ko s Direction of the cross series of Teeth in a, Planorbis contortus. 6, Ancylus fluviatilis. c, Zonites radiatulus. d, Achatina acicula. e, Zua lubrica, Jf, Vitrina pellucida. g, Limax carinatus. h, Helix obyoluta. « The degree of curvature of the transverse row, and the variations which the curves show (being sometimes composed of arcs of circles, while at other times they are made up of short straight lines PHYLLIVORA. 59 lying in different directions), appear to influence the form of the teeth. « Of the rows taken longitudinally I need not say much, it being more easy to explain the variations in the teeth when the rows are regarded transversely. Suffice it to mention that in the centre of the mem- brane there is a longitudinal row of teeth of dif- ferent form to any of the rest (called a rachis by Loven);” being, in fact, the symmetrical normal tooth from which all the others more or less sym- metrically diverge as the longitudinal series are placed farther and farther from the central one. “‘ From reference to an ideal vertical section of a plate with its tubercle (fig. 19.), it will be evident that on viewing the whole vertically (fig. 20.) through |; the microscope (the object being | almost transparent), three outlines will generally be seen, that of the plate, that of the attachment of the tubercle to the plate, which I shall refer to as the Fig. 20. base, and that of the free points of the tubercle, which I shall speak of as the apex; the teeth will therefore be regarded as the plate and tubercle combined. ** The central plate and its tubercle differ from all the others on this membrane in being symmetrical. The /plate is of a subquadrangular form, often some- what longer than broad, having its sides slightly hollowed out, and its ends nearly straight (Limaz, fig. 21.), or with its anterior end (that nearest the Fig. 19. 60 PHYLLIVORA. base of the tubercle) somewhat bow-shaped, in which case this part overlaps the posterior straight edge of Fig. 22. Fig. 21, Limax carinatus. a, central ; 8, first ; c, intermediate ; d, outer lateral tooth. Teeth of Zonites radiatulus. a, central; 0, first 5 ¢, intermediate lateral teeth. the plate in front of it (Zonites radiatulus, fig. 22.). In some it is nearly square (Zonites), while in others PHYLLIVORA. 61 it presents the form of an inverted tapering triangle, with a rounded apex ( Amphipeplea). «‘ The form of the tubercle on the central plate is subject to much greater variation than its plate. Sometimes the tubercle is very large and attached to nearly the whole sur- face of the plate, leaving but a small free apex (Li- maz, fig. 21.). In other species the tubercle is small, and attached by its Tecihi of Zan tae base to the anterior por- 4, central; 3, first lateral tooth. tion of the plate (Zua, fig. 23. a). In another genus (Planorbis) we find that the tubercle is small, and has two apices (fig. 24. a). Fig. 23. Fig. 24. alestinl Teeth of Planorbis carinatus. a, central; 4, first; c, intermediate ; d, outer lateral tooth. The apex in some few instances projects beyond the edge of the plate (fig. 21. a.), and consequently lies above the base of the tooth next beyond it; but, in the majority of cases, the apex of the central tubercle does not project over the edge of its plate (fig. 21. a). * The lateral plates not only differ from the cen- 62 PHYLLIVORA. tral one in form, but also from each other as they approach the edge of the membrane. The general form is subquadrilateral, the anterior and posterior edges being subject to the same variations as those described with reference to the central plate, while the inner edge is always more or less convex, and the outer edge concave. In those species where the curve of the horizontal row is considerable, the plates as they approach the edge get narrower, and in these it is not unusual for them also to assume somewhat an § form on the one side, and its reverse on the other. In others, however, the lateral plates become gradually broader, and eventually twice as broad as the primary lateral plates. ‘“¢ The lateral tubercles vary nearly as much in the same individual as they do in different species. “Tf an ideal line be drawn longitudinally through the central tubercle, so as to divide it equally, it will be found that the two halves are precisely similar (fig. 20.),— but such is not the case with any of the lateral tubercles, those lateral tubercles which are nearest to the central tubercles are always more similar to it in general form than those at the edges,— indeed, that the tubercles become more un- like the central tubercle as their position is nearer to the edge of the membrane—the lateral tubercles, indeed, are merely modifications of the forms of the central tubercle,— and that these modifications are effected by the suppression of the prominence on the inner side of each lateral tubercle, and the simulta- neous increase of the corresponding part of the outer side. PHYLLIVORA. 63 * In Limax carinatus, and some allied species, we have this clearly exemplified, the changes from the typical form into that at the edge being very gradual, and showing every possible connecting link, fig. 21. a—d. But this gradual progression is far from being the case in all species. For example, a sudden and abrupt change in form is to be seen in the fourth lateral tubercle of Zonites radiatulus, fig. 22.c. This sudden change of form is owing to the absence of the connecting links, which a refer- ence to the progressive alteration in other species will readily supply. Wherever a straight transverse line is observable in the arrangement of the lateral teeth, all the teeth in that line are similarly formed, whether the right or left laterals are in the same line, as in Planorbis contortus, fig. 18. a., or divaricate from each other at the central tooth upwards, as in Achatina acicula, fig. 18.d., or downwards, as in Ancy- lus fluviatilis, fig. 18.b. Wherever the curve presents great angularity, as in Zonites radiatulus, fig. 18. c., there we find a sudden change in the form of the teeth, while in like manner a gradual curve (Limaz carinatus, fig. 18. g.) is the result of a gradually pro- gressive change in the form of the teeth, the degree of deviation from a straight line being exactly in proportion to the amount of change which takes place between the form of the central and edge teeth. “The following table gives some idea of the number of teeth in a transverse or horizontal row, of a few species, together with the number of rows upon the tongue, and the whole number of teeth on that organ. 64 PHYLLIVORA. Number of Number of Number of transverse teeth in teeth on rows. row. tongue. Arion ater - - - 160 110 17,600 Limax maximus) - - 160 180 28,800 carinatus = - - 80 100 8,000 Vitrinus pellucidus - - 100 75 7,500 Helix aspersa 2 = 135 105 14,175 nemoralis - - HSH: 100 13,500 —— pomatia - - 140 150 21,000 — obvoluta - . 170 90 15,300 — lapicida - - 150 80 12,000 — pulchella - - 65 30 1,950 —— cantiana - - 125 80 10,000 —— concinna - . 100 50 5,000 —— pisana - - 120 70 8,400 —— caperata = = 100 45 4,500 ericetorum~ - - 115 60 6,900 Zonites alliarius - - 45 25 1,125 cellarius - - 35 27 945 nitidulus = - - 55 65 Bay ss Succinea putris - - 50 65 8,250 Balanus obscurus~ - - 120 55 6,600 acutus - - 100 37 3,700 Zua lubrica - - 80 40 3,200 Pupa juniperi - - 100 40 4,000 Balea perversa - - 130 40 5,200 Clausilia bidens - - 120 50 6,000 nigricans - = 90 40 3,600 Limneus stagnalis - - 110 110 12,100 Ancylus fluviatilis - - 120 75 9,000 Velletia lacustris - - 75 40 3,000 * Since Limazx maximus heads the list with 28,000 teeth, and Helix pomatia follows with 21,000, it might be conjectured, perhaps, that size had some influence in the matter; but we find Helix aspersa and H. ne- moralis possessing nearly the same number, while Helix obvoluta—a shell very little, if at all, larger than Zonites cellarius — possesses more than fifteen times the number of teeth. PHYLLIVORA. 65 ** With reference to the actual size of the teeth, it will be convenient to take the 10,000th of an inch as the measuring standard; and therefore the num- bers that I shall now use in giving the dimensions of the teeth are to be regarded as so many 10,000ths of an inch. “ In Arion ater the central and their neighbouring plates are 25 long by 15 wide. In Limax maximus they are 20 long by 114 wide. In Bulimus ob- scurus the length of this plate is 7, while the average length of all in the row is 43. In Zua lubrica the length is 53, and the average breadth 43. In Clausilia nigricans the length is 43, and the average breadth 32. The primary lateral plates of Limneus stagnalis is 22 long by 123 wide. In Amphipeplea glutinosa the corresponding plates are 11} long and 10 wide, which happens to be precisely the size of the primary teeth of plates in Planorbis corneus. “ The teeth of Arionide and Limacide are much alike, and differ from Helicide in having a long pro- jecting single apex to the edge teeth. “ The Helicide, on the other hand, show a marked disposition to increase the number of apices by bi- furcation as they approach the edge. * Arion ater, Limax maximus, and L. carinatus, Vitrina pellucida, Zonites alliarius, Z. cellarius, Z. nitidulus, and Z. radiatulus have the edge teeth aculeate ; Helix fulva, H. aspera, H. pomatia, Zonites rotundatus, &c. have the edge teeth serrate.” — Thompson. The jaw in Limaces and Helices is single, in the upper part of the buccal cavity, and is more analo- F 66 PHYLLIVORA. gous to the lateral jaws of Limnea than to the upper of the two jaws of Neritina, and appears to be formed of the fusion of these jaws; for Planorbis corneus has the rudimentary lateral jaws of Lym- nea; in all the other species the jaws are reduced to a single strongly arched one, as if formed by the fusion of the three into one.— Moquin Tandon, 33. M. Moquin Tandon proposes to characterise the genera by the form of the upper jaws. In Helix the jaw is lunate, with three or more strong ribs across it, which end in well-marked marginal teeth (fig. 25.). In Arion, Bulimus, Clausilia, Pupa, and Vertigo, the front of the jaw is more or less strongly striated Fig. 25. Fig. 26. Fg. 27. i (p ! AUTON Jaws of Arion Jaw of Limax Jaw of Helix hortensis, magni- gagates, magni- pomatia, enlarged. fied. fied. across, and slightly denticulated and crenated on the lower edge (fig. 26.). In Limax, Zonites, Vitrina, and Succinea, the jaw is smooth, without any ribs, strizw, or teeth, but has a more or less prominent beak in the middle of its lower edge (fig. 27.). These characters appear to be permanent, as far as they have been observed, in the more restricted genera, as Vitrina, Succinea, Clausilia, Pupa, Ver- tigo, Limax, and Arion; but there are many ex- ceptions even amongst the European species of the ARIONIDA. 67 genera or subgenera of Zonites, Helix, and Bulimus : thus Helix elegans has the jaws of a Bulimus, Bu- limus acutus of a Helix, and Helix candidissima of a Zonites. M. Tandon proposed to move these species to those genera for these reasons; but, if his figures of the jaws of the different kinds are examined, it will be found that there are only a few of the ex- ceptional species. Fam. 1. ARIONIDA. Head and tentacles retractile* into the skin, which covers them as a sheath, being drawn into the cavity of the body; the end of their tail is as it were truncated, and furnished with a transverse lunate, or an erect longitudinal, gland on its upper edge; the respiratory cavity is in the front of the body, with the hole in the front of the mantle’s edge; and the orifice of the generative organs is placed on the right side, near, or immediately under, the respiratory aperture (fig. 28.). The shell is presented in very different degrees of development in the different genera, —it is very rudimentary in the only English one. 1. Arron Férus. (Land Soles.) Body elongate, lanceolate, united its whole length to the foot; back keeled, attenuated behind; * Ehrenberg proposes to call the tentacles of snails tenta- cula, and those of pond snails, which do not bear eyes, vibracula. F 2 68 ARIONIDA. mantle shield-like, simple, anteriorly ovate, granular; the orifice of the generative organs is immediately under the respiratory aperture ; subcaudal gland transverse, horizontal. The jaw narrow, striated in front, and crenulated on the edge (fig. 26.). Shell distinct, oblong, sometimes only spongy, or only a few granules in the substance of the mantle. The eggs separate, covered with a hard calcareous shell. They lay about 70 or 100. They vary from twenty-five to forty days in hatching, and the ani- mals attain their full growth in a year, but they begin to deposit their eggs a month or two before that period, a. Shell none, or hemispherical and spongy. (Lochea. ) 13. 1. ARION ater. Black Arion.—Tentacles black ; the side of the foot marked with transverse black lines; body with interrupted longitudinal grooves; shield minutely granular ; salll spongy, henna plorcel (fig. 28.). Fig. 28, Arion ater. Limax ater. Linn. Faun. Suec, 507.; Miiller, Verm. 2.; Drap. 122. t. 9. f. 3—6.; Sturm, Faun.; Nunneley, Trans. Phil. SociLeeds AG. tod. 1. t. Qf. Uo tede fle ot (Osta 4aloctos f. 1.— Limax rufus. Linn. F. Suec. 507.; Razoum.; Drap. ARION. * 69 123. t. 9. f. 6.; Sturm, Fauna, t. — Limax succineus. Miiller, Verm. 7. 203. —Limax luteus. Razowm.— Limax mar- ginellus. Schrank. — Arion empiricorum. Férus. Hist. Moll. 60. 17. t.1,2,3.; Alder, Mag. Zool. and Bot. ii. 105. Leach. Syn. Moll. 47. t. 8. f.1,2.; Forbes and Hanley, B. M. iv. 7. t. D. D. D. f.4. — Limax subfuscus. Lister, A. Ang. t. 2. f. 1.; Drap. H. 125.— Arion subfuscus. Férussac. — Arion rufus. A. albus and subfuscus. Mog. Tandon, Moll. Franc. ii. 10. t. 1. f. 1 —27.— Limax albus. Linn. S. N. i. 1081. — Arion albus. Feruss. Moll. i. 64. t.2. f.3.— Arion virescens. Mill. Moll. Main. 11. 1854. Var. emitting a yellow mucus. — Arion flavus. Férussac, H. Moll. Supp. 96. n.7.; Alder, Cat. North. 30.; Forbes and Hanley, B. M. iv. 9. 287. t. FF F. f. 2.— Limax flavus. Miller, Verm. ii. 10. Living under damp leaves, only coming to the surface in damp weather. The young specimens of the black variety are dull brown, with yellowish sides. They vary greatly in colour, from black to brown- ish rufous, yellow, and yellowish white; the keel is sometimes greenish; the edge of the foot is generally the same colour as the back, but in some of the dark varieties it is scarlet or yellowish, it is always lined with black. Some naturalists have considered these varieties as species; hence the number of synonyma. Mr. Nunneley believes that the variation of colour is “ occasioned by habitation and food, as in fields it is nearly always of a deep black, while in gardens, where the food is more various, it is found of various colours.” This does not agree with my experience, for I have found them of very various colours in woods, and under exactly similar circumstances, and at the same period. The calcareous particles, particularly of the red F3 70 ARIONID&. variety, sometimes form an irregular sub-hemisphe- rical spongy shell. It has a great geographical range, being found equally in Ireland and Norway, and Italy and Spain. It deposits its bluish eggs in a cluster, in May, at the roots of plants. It feeds on dead and living vegetables, and some- times, according to Mr. Power (Linn. Trans. 1x. 323.), on dead earth-worms. The country people consider the appearance of this slug as an indication of approaching rain; but this is rather to be accounted for by the moisture of the ground and of the plants. It is seldom, indeed, to be observed abroad during dry weather, for this would deprive the body of the moisture which is requisite for its existence. (Bingley.) A black slug (Arion ater), placed in a box of sand taken fresh from the sea, after emitting a quantity of mucus, became reconciled to his situa- tion, and commenced eating the sand to extract the organic matter. The fices were at first of a green vegetable colour, but were at length entirely com- posed of pure sand, the grains united together into their usual form by a little mucus. (Gray, Ann. and Mag. N. H. ii. 310. 1829.) b. Shell imperfect, rugose, rarely wanting. '(Prolepis.) 14, 2. Arion hortensis. Garden Arion. — Black, with grey longitudinal streaks; edge of the foot orange; shell imperfect, rugose, or wanting. Gf. 16;) GEOMALACUS. 71 Arion hortensis. Férus. Hist. Moll. 6. 5.t. 11. f. 4—6. viii. a. f. 2, 3, 4., Tabl. Syst. 18.; Gray, Med. Rep. 1821; Leach, Syn. Moll. 49.; Forbes and Hanley, B. M. iv. 10.t. F. F.F. f. 1.; Gray, Cat. B. M. 56. — Limacella concava. Brard, Hist. 121. (Shell.) — Limacellus variegatus. Turton, Man. ed. 1. 25. t. 3. f. 16. (Shell.) — Limax subfuscus. Pfeiffer, Syst. Ind. 4. 20. (?) —Limax hortensis. Blainv.; Gratel. Moll. Dax. 55. f. 4.; Michelen, 6. Var. 2. with a black streak on each side. — Limax fasciatus. Nilson, Faun. Suec. 3. — Arion cireumscriptus. Johnst, Edinb. Phil. Journ. 1828, v. 77. — Arion hortensis, var. 8. Alder, Mag. Zool. and Bot. iii. 105.— Arion (Prolepis) fuscus. Mog. Tandon, Moll. Frane. ii. 14, t. 1. f. 28—30. Inhab. woods, hedges, and gardens. Gray, 1817. The variety is greyish, spotted with black, and with a black fascia round the shield and body; the respiratory hole is anterior. The young is yellow or white, with black head and tentacles. Common in gardens near London, called the April Slug. Eggs phosphorescent. M. Tandon describes 11 varieties. 2. GEOMALACUS. Body rather depressed; shield granular; back rounded, convex, not keeled; subcaudal gland lunate, horizontal; respiratory aperture rather in front of the middle of the lower edge of the shield; foot divided into three equal longitu- dinal bands. 15. 1. GEOMALACUS maculosus. Spotted Irish Slug. — Intense black beneath, pale white back and shield, with numerous subequal yellow spots, generally more numerous in a line on each side of the body. E4 te HELICID. Geomalacus maculosus. Allman, Ann. §& Mag. N. H. xvii. 297. t. 2.; Mr. Gray, Mollusca, t. 280. f. 1.; Forbes and Hanley, B. Moll. iv. 12. t. FF F.f. 5. West Ireland, Kerry. W. Andrew, Esq., 1842. The subcaudal gland is small, and scarcely to be distinguished in specimens in spirits. These animals are difficult to keep alive in confinement. Fam. 2. HELICIDZ. Head and tentacles retractile, like the former; but the end of the tail is tapering, and destitute of any gland. The pulmonary cavity is generally in the front of the body; the respiratory hole is on the hinder part of its edge; and the orifice of the generative organs is placed near the hinder outer base of the right tentacle. The eyes are on the top of the clubbed eye peduncle. The tentacles are rarely wanting. This family contains more than half of the British land and fresh-water shells, that is, 72 out of 128 species. It has been divided into several genera, and there are many more exotic ones. Many Helices begin to reproduce before they reach their full growth. The eggs of most of the Helices of Bulimus obscurus, Clausilia nigricans, and Balea are opaque or opaline, and isolated. Those of Helix virgata are transparent. The eggs of HH. pulchella are united together into the form of a cup, often 3 or 4 times as large as the animal and its shell. Vitrina pellucida HELICIDA. 73 and Succinea also unite their hyaline eggs into a mass with some gelatinous matter. The eggs of Bulimus obscurus are large, roundish-oval; those of Clausilia nigricans are ovoid, and very large for the size of the animal, being nearly as large as the mouth of the shells. Those of Balea are large and globular. The following table is formed from M. Bouchard’s observations. The first column exhibits the time of laying, No. 1. standing for January ; the second, the number of eggs laid at one time; the third, the number of days hatching; the fourth, the number of months before the animal arrives at its adult age. 1. PE 3. 4, Helix virgata = - - | 9—10 | 40— 60; 15—20 | 18—24 —— pomatia - - | 6— 9 | 60— 80) 20—30 13 — arbustorum - | 7—9 | 50 15—20 | 15—16 —-— aspersa- - | 5—10 |100—110} 15—30 13 — nemoralis - - | 5—10 | 50— 80} 15—20 | 11—13 — hortensis - - | 5—10 | 50— 80] 15—20 | 11—18 — carthusiana -|- - | 60— 80! 183—15 | 10—11 —— cantiana - - | 7— 8 | 60— 90} 14—15 11 —— fusca - - | 9—10 | 40— 50 20 10—12 —— pulchella - - | 7— 9 | 10— 20} 15—20 12 — hispida - - | 4— 9 | 40— 50 15 1516 —— rufescens - - | 7—10 | 40— 50) 20—25 | 11—14 —— ericetorum - - | 7—11 | 40— 60 20 18 — caperata - - | 7—10 | 35— 40} 15—20 12 rotundata - - | 5— 9 | 20— 30] 13—20 12 Zonites nitidus = - | 3— 9 | 30— 50) 15—16 14 Vitrina pellucida - - | 9—11 8— 15} 15—20 | 8—10 Succinea putris - - | 5— 9 | 50— 70) 14—15 | 11—12 Bulimus obscurus - 3.1) G59) WO 15 15: 13 Clausilia nigricans -|- - | 10— 12] 18—20 | 22—24 Balea fragilis = - -| 7—9 | 12— 15} 15—20 12 74 HELICIDA. They have been distributed into sections in the following manner : § 1. bd § 2. Scutifera. — Body elongate, attached the whole length of the foot; mantle shield-like, with a small internal shell. (Zimacina.) . Limaz (fig. 29.). Cochleophora. — Body more or less spiral, prominent on the (middle generally) upper sur- face of the foot, and covered with a more or less spiral shell. Sometimes partly hidden by the reflexed part of the produced edge of the mantle. Mantle produced in front, and partly extended over the shell. (Vitrinina. ) . Vitrina, Shell depressed, polished; mouth semilunar, large; peristome thin. ** Mantle enclosed, not produced in front. Zonites. Shell depressed, polished; mouth semilunar ; peristome thin, acute. Helix. Shell subglobose or depressed, striated ; mouth semilunar ; peristome rather thickened and reflected. . Succinea. Shell oblong, elongate ; mouth very large, oblong; peristome thin. . Bulimus. Shell oblong, elongate, striated ; mouth moderate, ovate, toothless. . Zua. Shell oblong, elongate, polished; mouth moderate, ovate, with a thickened internal edge. . Azeca. Shell oblong, elongate; mouth mode- rate, toothed, with a thickened internal edge. LIMAX. 75 9. Achatina. Shell turreted, elongate; mouth ovate ; inner lip truncated in front ; peristome thin. 10. Pupa. Shell cylindrical, blunt ; mouth sinu- ous; peristome reflected. ll. Vertigo. Shell cylindrical, blunt; mouth toothed; peristome thickened behind. 12. Balea. Shell fusiform, elongate: mouth ovate, clausium none. 13. Clausilia. Shell fusiform, elongate; mouth toothed, with an elastic clausium. § 1. Scutifera. — Body elongate, attached the whole length of the foot. 1, Limax Fer. (Slug.) Body elongate, lanceolate, granular, keeled behind; mantle shield-like, ovate, concentrically lined ; shell internal, sub-quadrate, flat, nail-like (fig. 29.). These animals have very much the external ap- pearance of Arion; but they are destitute of the gland on the end of the tail, their mantle is marked with circular striz instead of being granulated, and they have a different nervous system, for, according to Mr. Nunneley, the infra-cesophageal ganglion is like that of Arion, but the under side, instead “ of having one transverse fissure, has two, so that it presents, on each side of the medial line, three gan- gliform eminences instead of two only.” Jaw strong, smooth, with a strong central projection (fig, 27.). 76 HELICIDA. They have generally been united with the Arions : but it has lately been discovered that there are animals with well-developed shells that agree with the Arions in character, as the Helices do with the Slugs; and it has therefore been thought better to separate them by the above character into two groups, rather than follow Lamarck in dividing these animals into groups, by the gradually and greatly varying form of the body. The shells are covered with a distinct periostracum. It has generally been believed that shells which are covered with a reflexed portion, or imbedded in the mantle, are destitute of this covering; and they have been separated from other shells for this reason. But this is an error arising from the theory that the periostracum of shells is analogous to the scarf-skin of vertebrated animals, instead of its being merely the part, consisting almost entirely of animal matter, that is first deposited by the animal when it is about to enlarge its shell, and which forms the basis of the new part of the shell, afterwards strengthened and thickened by the addition of the chalky matter within it. These animals sometimes suspend themselves by a kind of thread formed from the viscid secretion which covers their body ; hence one of the smaller ones has been called Limax filans. The eggs are covered with a transparent coat, and are often united together by a membrane like a string of beads. They are laid between May and September. They are hatched in about 25 or 30 days, and the young reach their full size near the end of the year. Limax LIMAX. ray cinereus lays about 50 or 60, and L. agrestis is much more prolific, as 1t continues laying from April to the end of November, depositing 30 to 70 eggs each time, two individuals having laid 348 eggs in that period. ‘The young grow very rapidly. They commenced laying eggs on the 66th day of their age, when they did not reach their full size until the 92nd day. Swammerdam (Bz. Nat. i. 158. t. 8.) gives some details of the anatomy of one of the species; but recently Mr. Nunneley, in the Leeds Transactions, has given an excellent paper on the comparative anatomy of three of the species, and has shown that there exists a considerable difference in internal or- ganisation between them and the Arion ater. I have great pleasure in referring the reader to this paper for the details, and cannot help expressing a hope that other persons residing in the country will be induced to follow Mr. Nunneley’s excellent example, and give to the world similar papers on the animals in their neighbourhood. a. Back rounded; tail keeled; the dorsal shield marked with two orders of concentric strie, simple, rather produced behind ; shell flat. (Limax.) 16. 1. Liwax maximus. Spotted Slug. — Animal ash, variously spotted, with a long white acute keel; the tentacles vinous coloured, and the hinder part of the mantle produced, buckler- shaped (fig. 29.). Shell thin, flat, oblong, a little concave, with a membranaceous edge. (t. 3. £14.) 78 HELICIDA. Limax maximus. Linn. S. N. t. 3. f. 6. 10. 108.; Penn, B. Z. iv. 41. — Limax maculatus. Leach, MSS. Brit. Mus., in Syn. Moll. 52.; Nunneley, Trans. Phil. Soc. Leeds, i. 46.t. 1. f. 2., and Anat. — Limax maximus cinereus. Lister, Ez. Anat. t. 3. f. 6. 10.— Limax cinereus. Miiller, H. V. 5.; Drap. 124. t. 7. f. 10.; Sturm, Fauna, t.5.; Forbes and Hanley, B. M. iv. 15. t. D.D.D. f.1.; Gray, Cat. B. M: 163. — Limax ater. Razoum. — Limax fasciatus. Razoum. Limax cinereo-niger. Nilson, 7.; Wolf in Sturm, Fauna, t. 6. — Limax antiquorum. Férus. Hist. 68. t. 4. t. 8. a. f. 1. t. 4. f. 4. (Shell.) Leach, Syn. Moll. 51.— Limax (euli- max) maximus. Mog. Tand. Moll. Frane. ii. 28. t. 4. f. 1—8.— Cochlea nuda, s. domestica. Swam. B. Nat. i. 158. t. 8.; Lister, Ang. t. 1. f. 151. — Limacella Parma. Brard, 110. t. 4. f. 1,2. 9,10. (Shell.) — Limacellus Parma. Turton, Man. ed. 1. 1. 3. f.14. (Shell.) ; Lister, Ang. t. 1. f. 15. TInhab. cellars. The skin has small rugosities placed in lines con- verging towards the tail. The foot is divided into three nearly equal bands. Fig. 29. Limax maximus. The animal is very variable inits colour. 1. Red- dish brown, with four longitudinal, black, interrupted stripes, and the shield black-spotted. 2. Brown, black-spotted, back with three yellow, and two black lines. 3. Brown, with rather darker streaks. 4. Brown, black-spotted. 5. Ash, with a black shield; and 6. Black, with a white keel: the latter is L. cinereoniger of Nilson. Shell about six lines long and four broad, thin, semitransparent, yellowish-white, concave on the LIMAX. 79 inside, which is sometines sprinkled with minute erystal-like shining particles, a little convex and transversely wrinkled on the outside ; with the edges membranaceous; on the top, or broader extremity, is a small central prominence, or apophysis of ad- hesion, by which it is attached to the animal; the lower extremity very thin and rounded. When uritated, they dilate their shields. Their eggs are white, and deposited in spring under stones &e. These animals (especially the larger slug) are often infested with mites, which were discovered by Réaumur, in the Mém. 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