﻿SUPPLEMENT TO THE BIVALVIA. 



7 



Length, 2 inches ; height, \\ inches. 

 Locality. Dulwich. 



Several specimens of this species have been put into my hands by Mr. Meyer and 

 Mr. C. Evans, but they have all the valves united, or have the shell embedded in the 

 matrix so as not to exhibit clearly the dental furniture, or impressions by the muscles. 

 Mr. Meyer has, however, so far cleared the hinge of a left valve as to show that it has 

 two unequally elongated, lateral teeth, with what seem to be two triangular, cardinal 

 denticles, and a ledge for an external or ligamentous connector ; so that we can con- 

 fidently place it as a Cyrena. The large specimen which I have had figured, and which 

 belongs to Mr. Meyer, is smooth ; but there are two nearly obsolete rays. In other 

 specimens, however, these rays are more numerous, and vary from G to 10. 



I have given representations of some different forms. One of these has the posterior 

 or siphonal side somewhat pointed, and another has this side broader, and the shell is 

 nearly cylindrical, the posterior side being as broad or high as the anterior. 



A full description of this species was given by Mr. Edwards, as above referred to. 



7. Cyrena intermedia ? Melleville. Tab. A, fig. 8 a, b. 



Cyrena intermedia, Mellev. Sab. Tert. infer. Bas. de Par., p. 35, pi. ii, figs. 5, 6, 

 1843. 



— — Prestwich. Quart. Journ. Geol. Soc, vol. x, p. 155, pi. ii, 



figs. 10, 11, 1854. 



— — ? Desk. An. sans Vert, du Bas. de Par., p. 514, pi. xxxviii, 



figs. 19, 20, 1860. 



— (loxoptychodon) intermedia, Sandberger. Land- und Siissw.-Conch., p. 163, 



t. x, fig. 3, 1872. 



Spec. Char. C. Testa transversa, oblongo-subtrigond, inaquilaterali, obsolete trans- 

 versim striata; umbonibus prominulis obliquis, car dine tridentato, dentibus later alibus sub- 

 tequalibus, striatis. 



Length, fths of an inch. 



Localities. Britain : Charlton (S. Wood), Sundridge (Meyer). 

 France : Lignites. 



This shell corresponds with the one given by Mr. Prestwich, as above referred to ; 

 but I agree with him that its identity with the shell figured and described by Melleville 

 is doubtful, as Melleville's figure represents a larger shell with a narrower hinge, and more 

 rounded posterior side. I have therefore put a mark of doubt to the above name. M. 

 Deshayes has figured and described another shell under the name of C. Deshayesii, 

 Hebert, which rather more resembles our shell in having a more pointed posterior side, 

 but the umbo is less prominent, and the shell more inequilateral as well as larger. 



