﻿le 



EOCENE MOLLUSCA. 



dextrd poslerioribus dentibus duobm bijidis, dentibus lateralibus incequalibus, lavigatis ; 

 nymphis depressis. 



Length, 2-g-th of an inch ; height, 2 inches. 



Localities. Britain : Hempstead, Bembridge {Forbes). 



(and var. Wrightii) Headon beds, I. of Wight. 



This is a large and handsome shell, and deserving of the name given to it by 

 Mr. Sowerby, and I believe it is abundant at the above localities. It somewhat resem- 

 bles C. Lamberti, Desh., p. 495, pi. xxxix, figs. 9, 10, but differs in several particulars 

 from the figure and description of that species, which has a much longer fulcrum or 

 support for the ligamentous connector. 



The shell figured as C. Wrightii, Forbes, in the ' Memoirs of the Geol. Survey,' is 

 there regarded by Mr. Morris as a variety only of pulchra ; and following the opinion of 

 so sound an authority, I have not given Wrightii here as a separate species. 



22. Cyrena arenaria ?, Forbes. Tab. B, fig. 8 a, b. 



Cyrena arenaria, Morris. Catal. Brit. Foss., 2nd edit., p. 199, 1S54. 

 _ _ Forbes. Mem. Geol. Surv., Isle of Wight, p. 88, 1856. 



Spec. Char. C. Testa suborbiculari, subtequilaterali, tenui, concentrice et irregulariter 

 striata, umbonibus depressiusculis, area cardinali angustd ; dentibus lateralibus elongatis 

 incequalibus. 



Diameter, lfths of an inch. 



Locality. Headon Hill (S. Wood). 



The present shell was found by myself at Headon Hill half a century ago, before any 

 divisions of the Isle of Wight series had been worked out, and I am unable to say to 

 which division of the fluvio-marine group it may belong. I have given it under the 

 above name with doubt, in consequence of Forbes' species arenaria not having been 

 figured or described. The hinge of the specimen figured is much narrower than is that 

 of pulchra, and the shell itself is much thinner than in that species. Two of the cardinal 

 teeth in each valve are bifid, but the lateral teeth are narrower and more elongated than 

 those of pulchra, but none of them are quite perfect. 



23. Cyrena tenera, 8. Wood. Tab. B, fig. 9. 



Spec. Char. C. Testa tenera, ovalo-oblongd, laevigata ; valde incequilaterali,. 

 cxtremitatibus obtusis, umbonibus minimis depressis, obliquis ; cardine angusto. 



