﻿ANODONTA 369 



vated, but the region below them full ; rather dark, olive or 

 ashy-olive with faint darker bands ; nacre white, scarcely 

 pearly, much thickened in front. 



Length no, height 6i, diam. 47 mm. 

 Anodonta ponderosa C. PfeiFFER, Deuts. L. and S. Moll., 1825, 



Pt. 2, p. 31, pi. iv, figs. 1-6. — RossMASSLER, Icon., IV, 1836, 



p. 24, pi. XX, fig. 282. — DupuY, Hist. Moll. Fr., 1852, p. 



604, pi. XVIII, fig. 12. — KusTiiK, Conch. Cab. Ano., 1853, p. 



13, pi. IV, fig. I. — Drouet, Nay. Fr., 1854, p. 2, pi. vi. 

 Anodonta cygnea var. ponderosa Simpson, Syn., 1900, p. 626. 



Quite solid and inflated, the nacre in front being thickened 

 much as it is in A. implicata. The region below the beaks is 

 decidedly full. 



\'ar. rostrata Rossmassler. 



Shell very inequilateral with a full, double posterior ridge, 

 which is carried out to the greatly elongated posterior termin- 

 ation. This is raised a little above the base and generally trun- 

 cate or subtruncate. 



Anodonta rostrata Rossmassi^er, Icon., IV, 1836, p. 25, pi. xx, 

 fig. 284. — Stabilise, Faun. Lug., 1845, P- 59. pl- ^^^ ^S- 70- 

 — Drouet, Nay. Fr., 1852, p. 14, pi. v, fig. 2. — Kuster, 

 Conch. Cab. Ano., 1853, p. 14, pi. iv, fig, 2. — Bourguignat, 

 Rev. et Mag., XV, 1863, p. 23, (also XIV, pi. xxi, fig. 5). 

 Anodoti rostratus Sowerby, Conch. Icon., XVII, 1867, pi. 11, 



fig. 4. 

 Anodonta cygnea var. rostrata Simpson, Syn., 1900, p. 627. 



There is an Anodonta rostrata Held in Isis, 1836, page 280. 

 I do not know whether it or that of Rossmassler was published 

 first, or whether the two are the same or not. 



The number of specific names bestowed on the Anodontas 

 of Europe must run up into the thousands. I have gone over 

 the literature as carefully as possible, and large series of spec- 

 imens from many localities, and I confess that I am absolutely 

 unable to separate these forms specifically. The variations of 

 form, size, color, solidity, and even texture are sufficient for 

 a large number of species if they were not everywhere con- 

 nected by intermediate examples. The new school of conchol- 



