318 
MOLLUSCA. PECTIN IBRANCHI A. Neeita. 
neritadj:. 
* Marine. 
Nerita. 
Natica. 
** Fluviatile. 
Neritina. 
Gen. LVII. NERITA. — -Pillar-lip flat, entering the cavity, 
entire behind. 
270. N. llttoralis. — Whorls five, nearly smooth, the outer lip 
thin on the edge, thickened within. 
Nerita ex fusco-viridescens, List. An. Ang. 164, t. iii. f. 11, 12, 13. Conch, 
t. Dcvii. f. 39-44 — N. litt. Linn. Syst. 1253. Mont. Test. Brit. 467. 
— Common on sea rocks, covered with the tide. 
Length and breadth about three-quarters of an inch. Shell thick and 
strong, variously coloured ; whorls increase rapidly, spire short, depressed, 
the separating line small ; aperture semicircular, but the pillar is more round- 
ed anteally, where it joins the outer lip, than is usual in the genus ; hence 
Lamarck has placed the shell in the genus Turbo {T. retusus., Hist. Vert. vii. 
48.) ; a subperforation appears on the pillar. This shell is subject to consi- 
derable variation in the shape, arising from the spire being more or less pro- 
duced ; the body-whorl round or compressed, and the outer lip retrally join- 
ing the upper or middle part of the whorl. 
.271. N. Virgmea. — Smooth, polished; pillar-lip toothed. 
Nerita, List. Conch, t. Dcvi. f. 35. Turton’s Conch. Diet. 127 — West 
coast of Ireland. 
Breadth of those found by Dr Turton hardly the eighth of an inch, pale, 
ferruginous, with black zigzag lines running in various directions ; whorls lit- 
tle raised, a black line round the junctions. 
EXTINCT SPECIES. 
1. N. IcBvigata — Pointed, smooth ; spire conical, with straight sides ; base 
convex — Sower. Min. Conch, t. ccxvii. f. i Inferior Oolite. 
2. N. sinuosa Obtuse, uneven ; spire short, with convex whorls ; aperture 
with a rounded sinus near the base, and an angular sinus near the middle. — 
Sower. Min. Conch, ccxvii. f. 2 — Portland Oolite at Chilmarsh. 
3. N. glohosa — Subglobose, transversely sulcated ; spire apparent ; one tooth 
upon the inner lip ; outer lip plain within — Sower. Min. Conch, t. ccccxxiv. 
f. \. ^London Clay. 
4. N. aperta — Subhemispherical, smooth ; spire visible, depressed ; aper- 
ture orbicular, expanded ; inner lip obscurely crenated, bearing one large 
tooth. — Sower. Min. Conch, t. ccccxxiv. f. 2, 3, 4. — London Clay. 
5. N. minuta — Hemispherical, smooth ; spire indistinct, aperture oval ; 
pillar-lip not toothed.-— Min. Conch, t. cccclxiii. £ 3, 4. Oolite at An- 
cliff. 
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