The Shell-Collector’s Handbook. 83 
ANCYLUS FLUVIATILIS, MULL. 
SHELL dextral, conoid, with the point recurved, and ex- 
central, thin, yellowish-grey or horn-colour, and strongly 
marked with regularly arranged strize, which radiate from 
the apex to the peristome, but more finely striate in line 
of growth; mouth ovate, nearly a quarter of an inch in 
diameter. Height of shell 4-3th inch. Animal slaty- 
grey, spotted with black, sinistral. 
Hatitat.—In streams and rivulets attached to stones, 
or the shells of Unios and Anodons. 
v. capuloides (Jan.): Shell elevated, very convex 
anteriorily and laterally, nearly convex behind; aperture 
oboval, rounded. (= Ancylus capuloides. Jan. in Porro! 
Mal. Com. 1838, p. 87, pl. i., fig. 7.) 
v. costata (Fér.): Shell whitish or greyish, ornamented 
with very strongly marked striz. (Ferussac. 1822, Art. 
Ancyl. in Dict. hist. nat. de Bory Saint-Vincent, t. 1., 
p. 436, No. 5.) 
v. stricta (Morelet): Shell very elevated, very convex 
in front, compressed laterally ; aperture elliptical, narrow. 
(=Anceylus strictus, Morelet, Moll. Portug., 1845, p. 88, 
pl. vui., fig. 4.) 
v. gibbosa (Bourg.): Shell slightly elevated, extremely 
convex, sub-gibbous in front, convex laterally, nearly 
straight posteriorly; apex obtuse, overhanging posterior 
margin; aperture oboval. (=Ancylus deperiditus, Dup., 
Hist. Moil., 1851, v. p. 494, pl., xxvi., fig. 4; non Desm.— 
A gibbosus, Bourg., Cat. Ancyl, in Journ. de Conch., 1858, 
p. 185.) 
v. albida (Jeff.): Shell milk-white, and more finely 
striated, (B. C., vol. i., p. 120.) 
ANCYLUS LACUSTRIS, LINN. 
SHELL sinistral, semi-ovate, with the vertex subcentral, 
horn-colour, tinged with yellow or green, thin, glossy, com- 
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