﻿SUPPLEMENT TO THE EOCENE BIVALVIA. 



UNIO. Phillippson, 1788. 

 For generic character see 1 Eocene Mollusca (Bivalvia),' Vol. I, p. 130. 



Seven species of this genus were figured and described by myself in the Volume 

 of the Palseontographieal Society's Publications issued for the year 1862, and I 

 have here introduced the figure of another form. Some of these were not in perfect 

 condition, and will require confirmation by better specimens than any I have seen ; 

 indeed, one of these shells figured and described under the name of Unio Edwardsii, 

 p. 133, T. XX, f. 16, a b, very doubtfully belongs to that genus, the cast only with a 

 mutilated specimen being all that I had seen ; but they were so called in Mr. Edwards's 

 cabinet, and I did not feel justified in altering their names, as from their shape I thought 

 they might belong to the genus Unio. Another specimen has been obtained from the 

 same formation and locality by Mr. C. Meyer, but as this has only the exterior exposed, 

 I am still doubtful as to its generic position. It was referred to Cyrena by Mr. Meyer, 

 but with a doubt, and as I am inclined to think, in the absence of a view of the hinge 

 which the nature of the matrix rendered impracticable, that Mr. Meyer's view of the 

 genus is the more probable, I have figured it under the generic name of Cyrena 

 (Tab. A, fig. 15), so that if future specimens should confirm the reference, Unio 

 Edwardsii must be expunged from the list of Eocene Mollusca. 



The genus Anodonta does not so far as I know make its appearance in the Lower 

 Tertiaries of England, and only two species are given by M. Deshayes from the Paris 

 Basin ; these do not appear to be well established, and the exterior only has he repre- 

 sented (see his description, An. s. Vert, du Bas. de Par., vol. i, p. S0O). 



Unio Michaudi ? Deshayes. Tab. A, fig 6. 



Unio Michaudi, Desk. An. sans Vert, du Bas. de Par., p. 802, pi. lxii, figs. 1 — 5, 1860. 

 — — 1 Sandberger. Land- und Siissw. -Conch., p. 177, pi. viii, fig. 1 (cop. 



Desb.), 1872. 



Spec. Char. " U. Testa variabili, ovato-rotundatd, plus minusve inflato-yibbosd, valde 

 inaquilaierali, transversim irreyidariter rugosd, inaqualiter bis terve undato-yibbosa, smpius 

 postice plicis tenuibus, divaricatis ornatd ; umbonibusmaynis, tumidis, proeminentibus, sub- 



A 



