BIVALVIA. 203 



Venus literata. Linn. Faun Suec. non Syst. Nat. 



Capsa crocea. "Leach." Mag. Nat. Hist., vol. xx, p. 2/2. 



PuLLASTRA ACREA. Alder. Catal. Moll. North, and Durh., p. 86. 



Tapes ausea. Forb. and Hani. Hist. Brit. Moll., vol. i, p. 392, pi. xxv, fig. 5, 1848. 



Spec. Char. Testa ovafd, siib-cordatd, timidiusculd, siih-incequilaterali,postice angulatd ; 

 margine ventrali arcnato ; concentrice sulcatd; striis radiantibus obsoletis; lunuld cordato- 

 ovatd. 



Shell ovate or heart-shaped, slightly tumid, inequilateral, posterior side angulated ; 

 ventral margin convex, concentrically sulcated, with obsolete radiating striae ; an 

 elongated but not well-defined lunule. 



Length, l|-th of an inch ; height, i^ths ditto. 



Localities. Mam. Crag, Bramerton. 



Uddevalla. 



Recent, Norway, Britain, Mediterranean. 



The Mammaliferous Crag is its earhest appearance ; one specimen only is all that 

 I have seen, and that was found by Mr. Wigham, near Norwich, who has obligingly 

 permitted me to have it figured. In the recent state this is a common species in the 

 British seas upon the Eastern Coast, where it is subject to considerable variation, both 

 in regard to form as well as in the external ornament, some specimens being, in fact, 

 smooth, while others are deeply sulcated, or covered with regular ridges over the 

 entire surface. The striae upon the exterior of our solitary fossil specimen are fine and 

 numerous ; the anterior and posterior sides are somewhat compressed, while there is a 

 tumidity about the middle of the shell differing therein from the preceding species, 

 from which it also differs in being less elongated and rather less inequilateral. 



3. Tapes perovalis, S. Wood. Tab. XIX, fig. 7 a—d. 



Pullastka PEROVALIS. iS. Wood. Catalogue, 1840. 



Spec. Char. Testd elongato-ovatd, inaquilaterali, lumidd, nitidd, politd, tenui ; antice 

 rotundato-angulatd ; margine dorsali postico convexiusculo. 



Shell elongately ovate, inequilateral, tumid, smooth, glossy, and thin ; anterior side 

 roundedly pointed ; dorsal margin slightly convex. 



Length, 2 inches ; height, \\ inch. 



Locality. Cor. Crag, Ramsholt. 



I have obtained at the above locality about a dozen specimens of this species, 

 which from loss of animal matter had become excessively fragile. 



In many of its characters it strongly resembles Venus geog^-aphica, but the smooth 

 surface or total absence of the transverse ridges, as well as the radiating or decus- 

 sating striae which ornament that species, will readily distinguish it. A shell figured 

 and described by Phillippi from the Neapolitan seas, V. nitens. En. Moll. Sic, vol. ii. 

 p. 35, t. xiv, fig. 14, seems to approach even nearer, and may probably be identified 



