History of British animals - University of Guam Marine Laboratory

Emarginula. MOLLUSCA. FISSURELLAD^. 36'5Dr Turton (Conch. Diet. 142. t. xxii. f. 81.) describes a shell as PatellaNubecula, List. Conch, t.Dxxxix., belonging to this genus, in the followingterms ": Shell oblong, oval, sometimes a little contracted in the middle,semitransparent, a little convex, white, with red or brownish rays, which arebroader or narrower, sometimes interrupted, and often not extending quiteto the crown, with numerous obscure longitudinal ribs, and a few irregulartransverse furrows, which give it a rather rugged appearance towards themargin, crown not quite central, with an oblong perforation round which isoften a purplish ring ;inside white, glossy, with a purplish ring round theperforation at the bottom the ; margin plain : length |ths of an inch ; breadthand height about |ths These shells have been frequently brought to us, ashaving been dredged off the Land's End, on the Cornish coast ; but it has notoccurred to us, as yet,to find them ourselves.EXTINCT SPECIES.' :1. F. grceca 9— Ovate, oblong, convex, radiated ; radii decussated by elevatedlines, and thickened at the intersections ; perforation small, elongated ;margin of the base crenulated." — Sower. Min. t. cccclxxxiii.—In Crag, Ipswich.2. F. calthrata.— An elevated curved cone ; sides coarsely reticulated ; longitudinalribs about six on each side, and one central, which is split morethan half way down from the apex base oval ; ; apex bent almost down tothe base.— Sower. Min. Conch, t. cxix. f. I.— Oolite at Ancliffe.Gen. LXXXIX. EMARGINULA— Conical, the anteriormargin of the aperture with a longitudinal slit ; tentaculaon footstalks ;foot fringedwith filaments.—364. E. Jissura.— Strongly cancellated by longitudinal andtransverse ribs;apex reflected.Patella exigua,List. Conch, t. Dxliii. f. 28.— P. fissura, Linn. Svst. i.1261. Penn. Brit. Zool. lv. 144. t. xc. f. 151.t. iii. f. 2. Mont. Test. Brit. 490—Various partsDon. Brit.of the coast,Shells,notcommon.Length half an inch, breadth and height |ths ; subpellucid, brown whenalive, white or flesh-coloured when worn ; longitudinal-ribs strong vertex;more or less reflected, margin oval, crenated ;the branchial slit extendingabout one-fourth of the height of the shell ; inside glossy flesh-coloured—Mr Bell describes a shell apparently belonging to this species,in the Zool.Journ. i. 52. t. iv. f. 1., as having been found at Poole Harbour, under thetitle E. rosea. It only differs from E. fissura in the variable characters of theapex being higher and more recurved, and the inside of a delicate rosecolour.EXTINCT SPECIES.1. E. crassa.— Oval, obtusely conical, furrowed ;with four or five strise betweeneach furrow ;fissure wide—Sower. Min. Conch, t. xxxii., upper figuresIn Crag, Ipswich.2. E. reticulata.— Shell oval, reticulato-striated, vertex rather acute; principalradii twenty-four or more—Soiver. Min. Conch, t. xxxiii., lower—figures.In Crag ? Holywell.3