Illustrations of the recent conchology of Great Britain and Ireland, with the description and localities of all the species, marine, land and fresh water

Pu Yl,T,IDTACEA.] MOLLUSCA. 65 Shell ovale, subpelluci<l, providecl with from ten to twelve moniliform, tesselated, red rays; apex acute, ancl submarginal; ground colour of the exterior of an opaque reclclish-white. Length somewhat more than a quarter of an inch ; breadth about a fourth narrower than its len<>th. This shell was discoverccl by Prof~ssor Forbes, on the Manx coast, aclhering to shells in decp water, who says it is allied to th: .Patclla virginca., but differs from that species, in never at- tammg so large a size; ami in the markings, especially in the young shell, being of a bluish-white colour, with red rays. GENUS 18.-CHITON,-Linnrous. ShelJ elongated, or oblong-oval; consisting of eight valves, placed transvcrsely on the back of the animal, which is convex; these valves are moveablc ami imbricated, the edge of the one resting on that below it, the terminal ones bcing roun<lcd cxte- riorly; valves surrounded by a coriaccous marginal skin, or ligamen! ; severa\ of the vah-cs are provide<l with marginal teeth, which are, however, concealed by the marginal liga- ment. Scction I.-Mcwginal ligament spinous. 1. CHITON FASCICULARIS, pi. XXI, f. 5 and 8. Chiton fascicularis, First Ed., pi. 35, f. 5 ancl 8; Linné, p. 1106; Montagu, p. 5, pi. 27, f. 5; Maton ami Rackett, p. 21, pi. 1, f. 1 ; Brown, Ency. Brit., p. 402; lb., Werncrian Mem., p. 503; Fleming, p. 288; lb., Edin. Ency., VII, p. 103; La- marck, Syst., VI, pt. 1st, p. 321 ; Lowe, Zoo!. J ourn., II, p. 96; Ency. l\leth., pi. 162, f. 15; Forbes, p. 37. Shell subcarinated; the carina of the valves longitudinally striated, their sides thickly studdcd with coarse, clevated gra- nules, which are distinct to the naked eye; the centre of the first ami last valves dcslitutc of thc longitudinal striro; ligamen- tary margin also provided with coarse granulations, more or less spinous, and furnished with fasciculi of grayish, shorl bristles, situate at the intersticcs of the valves, on the sides, and round the firsl and terminal vah-es; marginal teeth of the valves Yari- able, sometimes having thrce notches on each side, with the intermediate space crenulated; thcse crenulations are sometimcs so deep in the last valve, ancl reach within a short clistance of cither extrcmity, that they may almost be considered as tecth; the colour is variable, generally cinereous, or clark olive-green; marginal fringe very distinct, and bristly. Length varying from a quarter to three-quarters of an inch; breadth somewhat more than half its length. This species seems liable to variety, as it will be noticed that fig. 8, which was drawn from one procured by Dr. Goodall on the rocks at vV eymouth, has twenty-one tufts of hairs, one of which is placed 011 the extreme point of the terminal valre, whilc, in general, only twenty fasciculi are met with, none being on the terminal vah•c. Montagu says that this species has only eightecn tufts. This shell is not uncommon on many of the 13ritish coasts; and is a cleep water species, generally found atlachecl to oysters and stones. The very fine specimcn from which fig. 5 was <lrawn, was procured at Lough Strangforcl, County of Down, Ireland, where it is plentiful of that size. The smaller one, fig. 8, is not uncommon in the Frith of Forth. R 2. CHITON DISCREPANS, pi. XXI, f. 20. Chiton discrcpa11s, First Ecl., pi. 35, f. 20; Chiton -- ? Ency. Meth., p. 163, f. 11, 12? Shell much elongated, narrow, acutely carinated; vah·es shielcl-shaped, ami acutely pointecl beneath; along the centre of the vah-es is a lance-shapecl elevation, which is striated lon- gitudinally; ,·ah·es covered with strong, round, elevated, regu- larly set papillro, except at the edges, which are plain; at thc junction of each vah-e is a tuft of strong, straight, stiff bristles; whole margin beset with rather distant, very minute, gray hairs ; valves generally of an orangc-yelJow; margin dccp umber- brown. This spccies differs from the preceding in being much more carinatcd, in the vah·es being a third narrower, in the fasciculi of bristles being shorter and more stunted, in the papill<ll being round inslead of oral, ami the whole shelJ being much narrower in proportion to its Jength. Severa! specimens of this shell, new to the Ilritish Concho- Iogist, were sent to me from George Lyons, Esq., of Tenby, ,vales, where it is common, ami where it was mistakcn for the C. fasciculm·is. 3. CHITON CRINITUS, pi. XXI, f. 20. Chiton c1·init11s, First Ed., pi. 35, f. 20; Peunant, IV, p. 71, pi. 36, f. 1, 1 ; Gmelin, Linn. Syst., p. 3206; Montagn, p. •1 ; Maton and Hackett, p. 20; Fleming, Edin. Ency., p. 103. "Shell with seven valves; thick set with short hairs ; five- eighths of an inch long. lnhab its thc sea, near Aberdcen."- Pennant. Mr. l3oys informed Montagu that he hacl ulso found it at Sandwich. Scction 11.-J11a1'{1i11al ligamcnt sti·iatcd, o,• papillose. 4. CHITON L,EVIS, pi. XXI, f. 10, 1 l. Chiton la:vis, First Ed., pi. 35, f. 10, 11; Pennant, IV, p. 72, pi. 36, f. 3; Montagu, p. 2; Ilrown, Ency. Ilrit., p. 40?; lb., Wernerian Mem., p. 503; Fleming, Edin. Ency., p. 102; lb., Brit. An., p. 90; Forbes, p. 37; Maton and llackett, p. 21. ShelJ with eight smooth, slightly carinated, pointed ,•alves, generally of a deep reddish-brown, mottled with white, but is liable to considerable variety both in colour and markings, with remole, nearly obsolete striro; margin broad, fringe very minute, with fine decussated striro. Length a little more than half nn inch; brcadth more than half its length. Found on many of the coasts of Great Britain and lreland, in deep water, although it may be considere<l a local species. First noticed in Loch 13room, Rossshire; the Frith of Forth, coast of Northumberland, Devonshire, Manx coast, and at Rathgarmont, Longh Strangford, Ireland. 5. CHITON ACIIATINUs, pi. XXI, f. 4, 12, 13, and 15. Chiton aclwtinus, First Ed., pi. 35, f. 4, 12, 13, and 15; Brown, Ency. Ilrit., VI, p. 402. Shell very oblong; valves narrow, an<l long in proporlion to their breadth, considerably elerated in the centre, but not cnri- nated; pale lilac-coloured in some specimens, and olive-green in others, bcautifully marbled with reddish-brown, and indis- tinctly striated transversely, following thc wave of the valves; both anterior an<l posterior t crminal valves are coverecl with transverscly arcuated striro, and the whole of them very minutely shagreenecl; margin with upright oval, minute spccks of sha- green.