m 
MOLLUSCA. PULMONIFERA. Segmektika. 
Gen. XXXIV. ANCYLUS. — Shell conical; foot short ; tenta« 
cula short, flat, and a little truncated. 
1^9. A.Jluviatilis. — ^Aperture suborbicular ; apex lateral. 
Patella fluviatilis, List. An. Ang. 151. Conch. 1. 141, f. 39. — P. lacustris, 
Linn. Syst. i. 1260, — An. fluv. Mull. Verm. ii. 201. — P. fluv. Mont. 
Test. Brit. 482. Don. Brit. Shells, t. 147.— On stones in rivulets, 
common. 
Length about |ths, breadth fths of an inch ; height nearly equal to the 
breadth; horn-coloured, with Concentric wrinkles crossed by faint lines ; apex 
pointed, a little recurved. 
130. A. lacustris. — Aperture oblong ; apex nearly central. 
Mull. Verm. 199 — Patella oblonga. Light. Phil. Trans. 1786, 168. t. 111. 
f. 1, 6 — P. lac. Mont. Test. Brit. 484. Don. Brit. Sh. t. 150 — On 
plants in ditches and lakes. 
Length ^th of an inch ; breadth ith, height scarcely J^th of an inch, thin? 
smooth, greenish, compressed ; apex low, pointed, recurved. 
EXTINCT SPECIES, 
1. A. elegans — Convex, subconical ; aperture longitudinally obovate ; apex 
oblique, eccentric, near the narrowest part of the aperture.— (S'ower. Min, 
Conch, t. 533 — Found in dark-grey sand of the Lmdon clay, at Hordwell, by 
Charles Lyell, Esq. jun. 
