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

62 MOLLUSCA. [GASTl!.ROPOD,\ GENUS 13,-EMhRGINULA-Lamarck. Shell conical, shield-shaped; destitute of spirnl convol~tiot~s; vcrtex inclined to the posterior ext remity; anterior ~argm w1th a fissure, or notch; interna\ cavity simple; anterior s1des ~f thc muscular impression interrupted, expanded, and not contmued across the fronf, 1. EMARGINULA F1ss un1,, pi. XII, f. 17 and 19. Emai-ginulafismi·a, First Ed., pi. 36, f. 17 and 19; Lamarck, Syst., VI, pt. 2 nd, p. 7; Brown, Conch. Text Book, p. 101, pi. 14, f. 17; lb., Popular Ency., II, p. 378, pi. 17, f. 97 ; Patclla fasura, Pennant, No. 152, p. 1'1•1, pi. 90, f. 151; Donovan, pi. 3, f. 2 ; l\íontagu, p. 490; Ilrown, 'Wernerian l\'Iem., p. 583; Fleming, p. 365; Forbes, p. 33; Martini, I, pl. 12, f. 109, 110; Da Costa, pi. 1, f. 4; l'l'!aton ancl Rackett, p . 236; Turton, Brit. Fau., p. 1!)8. Shell brownish-whitc, conic, subpellucid, an<l rather thick; surfacc furnishcd with longitudinal and conccntric stri.c, pro- <lucing a bcautiful lamcllatecl appcarance; vertex slight ly re- llected; anterior margin providCll wi th a longi tudinal fissure, or slit, cxtending about a fourth of thc length of the shell ; insidc whitc, smooth, and glossy, somctimcs of a skin colour; aperture oval; margin slightly crcnatecl. Lcngth half an inch ; hcight thrcc-cighths, and brcadth nearly thc samc. In thc young shcll thc vcrtcx is more refl cxed, ami in sorne instanccs is slightly hookcd, turni ng backwards ncarly to the anterior margin. Thc E.fisrnm is rathc r local, ami found on thc coasts of Dc.rsctshire, D cvonshirc, Cornwall, Kcnt, and Northumbcrland, in Englaml; thc Frith of Forth ami Clydc, Scolland; and al P orlmarnock, Ircland. 2 EMAIIGINULA ROSEA, pi. XII, f. 21, 22. E mai'gi,ml" rosca, First Ed., pi. 3G, f. 21, 22; Bcll, Zoo!. Journ., I, p. 52, pi. 4, f. l. " Shcll ornte, canccllatcd, covercd with a fuscous waved epi- dermis ; insidc rose-coloured; vertcx acule, vcry much incurved and subinvolute, pro1•icled with a marginal fissure."-Bcll. Found in l'oolc 1-farbour, by Thomas Ilell, Esq., who took threc specimcns by drcdging. GENUS l •1.-Sc1ssunELLA,-D'Orbigny. Shcll subelliptical, snbdcprcsscd; spirc short, small, ancl con- sistin" of t wo or thrcc yo(utions; apcrturc subornl, obliquc; lips scpar:tcd from cach othcr abore, 0 11 thc lcft sidc ; ontcr lip sharp on thc margin, with an oblong, decp slit, or foramen, situatc ncar th_c spirc, and almost parallel with the suture, ami is continucd cxternally as a subcarina; inncr lip somewhat rcílcclcd, with a largo umbilicus bchind it. Probably the situat ion which this genus should occupy, is in thc fa.mily T11rbi1wcc11. l. Sc1ssunELLA cn1srATA. Scissm·c/ln crispa/a, Flcming, Drit. An., p. 366. " T ransYcrscly ribbcd, and spirally striatcd; inner lip reílcctcd on thc body rnlution. "Brcadth nbout thc fiftccnth of an inch; whitc, and wi thout any apparcnt cnticlc; whorls thrcc, incrcasing rather rapidly from thc slightly clcratccl apcx, ami sloping with a gentlc con- Ycxity, from the .separating linc to thc keel; unclcr sidc with a central cavity, from which the whorls cxtcnd, a littlc eonvex to thc kccl. Thc whorls are marked by numcrous fine transverso arcuatcd ribs, narrower than thc intervcning spaccs, crosscd by fine longitudinal stri.c (most conspicuous on thc spaccs), giving to thc shcll its peculiar rcticulated appcarancc; thc ribs on thc uppcr sido are coarscr than thosc bclow. Thc apcrturc is sub- orbicular, slightly dcprcsscd ; the outer lip thin; thc inncr lip slightly rcílcctccl ovcr thc cavity, sprcad on thc body whorl, ancl continuous with the outer lip. From thc pillar cavity a shallow gutter extends anteally, and joins the pillar lip ; this is chicíly conspicuous on thc largest spccimens. Thc longitudinal sli! in the middlc of the outcr lip extcnds backwards about two-tlnrds of thc diametcr of thc shell, whcre it joins thc narrow groovc in thc kcel of thc shcll which it had formcrly occupicd. Thc margin of thc slit is slightly clcvatcd, as wcll as thc groovc, which is sccn winding round thc whorls al thc scparatiug linc, nearly to thc apcx ; thc groovc itsclf is slightly ribbcd across. I found this shcll in 1809, ami specimcns thcn transmittcd to Coloncl Montagu, wcre pronounccd by him thc fry of a Tro- clms, it is, howcvcr, a wcll markcd shcll, ancl belongs to thc gcnus S cissu,-cll" of M. D'Orbigny."-FlcmÍllg. Fouml by thc Rcv. Dr. Fleming, "in shcll sand, at Noss, Zetland, after a storm." fAMILY V.-SEMIPHYLLIDIACEA. Ilranchiro situate undcr the margin of thc mantlc, and sel in a longitudinal series, 011 thc right sidc of the body. Thc ani- mals respire undcr water. Gmrns 15.-PLEUI\ODilANcuus.-Cuvicr. Shcll placee\ intcrnally on the back of thc animal; halioti- form, thin, ílat, and obliquely oral; convex abovc, towards thc somewhat spiral apex, with a lateral, ncarly terminal, dcprcsscd vcrtex; apcrturc cntire. l. PLEUllOllllAKCllUS PLUMULA, pi. Il, f. 14, 15. Lamcllariti pl111n11la, First Ed., pi. 44, f. 14, 15; Plc1t1'0- bn111clms plmmda, Flcming, p. 2!)1; llrown, Conch. Tcxt Ilook, p. 102, pi. 14, f. 14; Smith, \Vcrncrian Mcm., VIII, p. 43 ; B1,ll" ¡,lmmtla, Montagu, p. 214, pi. 14, f. !) ; Ilrown, Ency., VI, p. 435; Turton, llrit. Fau., p. 1G8 ; Flcming, Ency., VII, p. 84 ; l\faton and llackctt, p. 183. Shcll oblong-oYatc, dcpresscd, 1·cry thin and pcllucicl, of a ycllowish \1orn-colour, with n vcry small couvolution placed ncar onc cnd; wholc surfacc strongly wrinklcd conccntrically, with tlirec radiating indcntat ions, cmanating al thc apcx, and terminating on thc lowcr margin; apcrlurc thc wholc leugth of thc shcll; insidc Ycry glossy, with nnclulations corrcsponding to thc wrinklcs on thc outsidc; pillar slightly inflcctcd, so as to form thc dcpresscd rnlution. Lcngth upwarcls of half an inch ; brcadth more than a quarter. Disco1·crecl by l\iontagu on thc rocks at l\l ilton Sands, sonth coast of Dcrnnshirc, ancl has sincc bccn fonnd in many parts of England, Scotland, ami Ircland. 2. P LEURODRANCIIUS ME~IUHA:-.ACElJS, p\, Il, f.!). Lamella,-ia mcmbnmacca, First Ed., pi. ,¡,¡, f. !) ; l\Iontagu, Linn. T rans., XI, p. 184, pi. 12, f. 3 ; Plcul'ob1·a11cltus 11wm- b,-mwccus, Flcming, p. 2!)1.