I'l^S' 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Bay, which is generally so. The surface is covered with irregular 

 fine laminae, slightly raised ; the umbones very small, and approxi- 

 mate. 



This species has been identified with an undescribed form from 

 Bracheux, given to Mr. Prestwich by M. Deshayes, but which is not 

 published. Named after the locality (the Reculvers) where this 

 species is most common. 



From Mr, Prestwich's collection. 



Cyrena cordata, n. sp. Pl. II. figs. 7, 8, 9. 



Testa subtrigonali, crassa, gibbosa, rugosa ; lunbonibus proniinentibuss, 

 antico rotundato, postico subrostrato, depresso, attenuate. 



The general form of this shell is trigonal ; the beaks are prominent 

 and incurved ; the ventricose character of this shell towards the 

 umbones gives it, when viewed anteriorly, a cordiform appearance 

 (whence the name) ; the posterior side is attenuated and slightly 

 truncate. The surface of the shell towards the anterior side is very 

 rugose by the lines of growth. 



This species is intermediate to C. cuneiformis and C. deperdita, 

 and also resembles in its cordate form the C. aniiqua of the Paris 

 basin ; it does not, however, possess the depressed character of the 

 posterior cardinal edge. 



From Mr. Lunn's collection. 



MoDioLA Mitchelli, n. sp. Pl. II. figs. 12, 13. 



Testa tenui, Isevi, subtrigona, antice obtusa, ]iostice dilatata ; cardine mar- 

 ginali recto. 



A somewhat trigonal, depressed, and dilated shell, with the um- 

 bones obtuse, the dorsal line straight, and the byssal margin nearly 

 straight, or but very slightly curved ; the surface nearly smooth, or 

 faintly marked by lines of growth. 



This species is near to Dreissena antiqua, Mell., but the dorsal 

 margin is more produced, and the general contour of the shell more 

 spathulate. 



Not rare in the upper part of the Woolwich series at New Cross, 

 Deptford, Lee, and Blackheath. It is rarely found perfect. Named 

 after the late Dr. Mitchell, who obtained the best-preserved specimens 

 of this shell at New Cross, during the cutting of the Croydon railway. 



Modiola dorsata, n. sp. Pl. II. fig. 14. 



A rare species — the specimen is hardly sufficiently perfect for an 

 exact determination of its characters. It differs from the preceding 

 species in the umbo not being so terminal, and the form being less 

 spathulate and more compressed. 



From Sundridge. Mr. Prestwich's collection. 



Psammobia? Condamini, n. sp. Pl. II. fig. l.o. 



Testa ovato-transversa, iusequilaterali, depressa, subiuaiquivalvi, concentrice 

 at iri'egulaviter striata ; niargine antico rotundato, postico rostrato, at- 

 tenuato. siniiato : mai-gine postico subincurvato. deelivi. 



