Paludina. MOLLUSCA. FECTINIBiiANCHIA. 315 
3. E. fConical, transversely striated, base angular, sides flattened, 
central cavity plaited or deeply striated ; aperture oblong — Cirus plicatus, 
Soioer. Min. Conch, t. cxli. f. 3. — Chalk Marl^ Folkstone. 
4. E. perspectivus Obtusely conical; spirally striated, central cavity deep, 
exposing one-third of each whorl ; aperture transversely oblong — Cirus per. 
Mant. Geol. 194. t. xviii. £ 12, 21. Sower. Min. Conch, t. ccccxxviii. f. 1, 2. 
— In Chalk. ' 
5. E. Subdiscoid, concentrically striated ; central cavity wide, 
exposing a small portion of each whorl ; an angular canal runs round the 
spire; aperture obtusely angular Cirus depressus, Mant. Geol. 195. t. 
xviii. f. 18, 22. Sower. Min. Conch, t. ccccxxviii. f. 3 — In Chalk. 
6. C. granulatm. — Conical; whorls five or six, obscurely quadrangular, or- 
namented with regular transverse granulated striae. — Mant. Geol. 195. — Up- 
per Chalk. 
7. C. Sowerbii Conical, spiral, smooth, umbilicate ; inner wreaths anchy- 
losed slightly inserted ; aperture indented by the preceding volution — Ver. 
micularia Sower. Mant. Geol. iii. t. xviii. f. 14. 15 . — Grey Chalk Marl. 
8. C. Bognorensis Spiral, last volution much produced, inferior side deep- 
ly umbilicatq. — ^Verm. Bog Mant. Geol. 272. 
Gen. LVI. PALUDINA.— -Shell conical, mouth a little long- 
er than broad ; pillar-lip simple. 
267. P. vivipara.^—Whovl^ five or six, rounded ; separating 
line deep ; apex like a minute tubercle. 
Cochlea maxima. List. An. Ang. 133. t. ii. f. 18. Conch, t. cxxvi. f. 26. 
— Helix vivipara, I Ann. Syst. i. 1247.' — Nerita viv. Mull. Verm. ii. 
182, — Hel. viv. Mont. Test. Brit. 386. — Cyclostoma viviparum and 
achatinum, Drap. Moll. 34, 36. — In the slow running rivers of Eng- 
land. 
Length sometimes an inch and a half, the breadth one inch ; olive-green, 
with three brown spiral bands ; whorls with an abruptly fine apex, irregular- 
ly wrinkled by layers of growth; the body- whorl occupying about two-thirds 
of the length of the shell ; aperture nearly semicircular ; pillar-lip a little re- 
flected, behind which is a small cavity ; operculum corneous ; concentrically 
striated. Young about ten in number — This varies a little in the shape of 
its aperture, and in the relative size and distance of the coloured bands. 
268. P. tentaculata . — Whorls five or six, a little rounded ; 
apex entire. 
Cochlea parva. List. An. Ang. 135. t. ii. f. 19. Conch, t. cxxxii. 32. — 
Helix tentaculata, Linn. Syst. i. 1249. — Nerita jaculator, M^llLYerra. 
ii. 185 — Hel. tent. Mont. Test. Brit. 389. — In stagnant waters, Eng- 
land and Ireland. 
Length half an inch, breadth one quarter, smooth, glossy, horn-coloured, 
with fine lines of growth ; whorls increasing less rapidly than in the preced- 
ing species, the body whorl occupying about the half of the length of the 
shell; aperture ovate, slightly contracted retrally ; pillar- lip a little reflect- 
ed ; tentacula setaceous, and continually in motion. The young of this spe- 
cies constitute the Nerita sphcerica of Muller, and the Cyclostoma simile of Dra- 
parnaud. 
269. P. acuta . — Whorls five or six, a little rounded, taper- 
ing ; apex entire. 
