Emarginula. MOLLUSCA. FISSURELLAD^. 865 
Br Turton (Conch. Diet. 142. t. xxii. f. 81.) describes a shell as Patellot 
Nubecula^ List. Conch, t. Dxxxix., belonging to this genus, in the following 
terms : “ Shell oblong, oval, sometimes a little contracted in the middle, 
semitransparent, a little convex, white, with red or brownish rays, which are 
broader or narrower, sometimes interrupted, and often not extending quite 
to the crown, with numerous obscure longitudinal ribs, and a few irregular 
transverse furrows, which give it a rather rugged appearance towards the 
margin, crown not quite central, with an oblong perforation round which is 
often a purplish ring ; inside white, glossy, with a purplish ring round the 
perforation at the bottom ; the margin plain : length |ths of an inch ; breadth 
and height about |ths. — These shells have been frequently brought to us, as 
having been dredged off the Land’s End, on the Cornish coast ; but it has not 
occurred to us, as yet, to find them ourselves. 
EXTINCT SPECIES. 
1. F. greeca ? — “ Ovate, oblong, convex, radiated ; radii decussated bj’’ ele- 
vated lines, and thickened at the intersections ; perforation small, elongated ; 
margin of the base crenulated.” — Sower. Min. t. cccclxxxiii — In Crag^ Ips- 
wich. 
2. F. calthrata . — An elevated curved cone ; sides coarsely reticulated ; lon- 
gitudinal ribs about six on each side, and one central, which is split more 
than half way down from the apex ; base oval ; apex bent almost down to 
the base. — Sower. Min. Conch, t. cxix. f. 1 — Oolite at Ancliffe. 
Gen. LXXXIX. EMARGINULA.— Conical, the anterior 
margin of the aperture with a longitudinal slit ; tentacula 
on footstalks ; foot fringed with filaments. 
864. E. Jissura. — Strongly cancellated by longitudinal and 
transverse ribs ; apex reflected. 
Patella exigua, List. Conch, t. Dxliii. f. 28. — P. fissura, Linn. Syst. i. 
1261. Penn. Brit. Zool. Iv. 144. t. xc. f. 151. Bon, Brit. Shells, 
t. iii. f. 2. Mont. Test. Brit. 490 — Various parts of the coast, not 
' common. 
Length half an inch, breadth and height |ths ; subpellucid, brown when 
alive, white or flesh-coloured when worn ; longitudinal-ribs strong ; vertex 
more or less reflected, margin oval, crenated ; the branchial slit extending 
about 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 the 
title E. rosea. It only differs from E. fissura in the variable characters of the 
apex being higher and more recurved, and the inside of a delicate rose- 
colour. 
EXTINCT SPECIES. 
1. E. crassa Oval, obtusely conical, furrowed ; with four or five striae be- 
tween each furrow ; fissure wide — Sower. Min. Conch, t. xxxii., upper fi- 
gures. — In Crag.) Ipswich. 
2. E. reticulata — Shell oval, reticulato-striated, vertex rather acute ; prin- 
cipal radii twenty-four or more. — Sower. Min. Conch, t. xxxiii., lower figures. 
— In Crag‘s Plolywell. 
3 
