200 MOLLUSCA FROM THE CRAG. 



Animal. 



This appears to be distinguished by its dental formula having no lateral teeth like 

 those in Cypricardia. What has hitherto constituted the genus Venerupis, is a greater 

 number of cardinal hinge teeth, being three in a parallel direction, whereas in this 

 there are only two diverging widely from the umbo. Tt appears to be closely related 

 to the Venus family, but at present little is known respecting the few species that have 

 as yet been noticed. 



1. CORALLIOPHAGA CYPRINOIDES. S. Wood. Tab. XV, fig. la — d. 



CoRALLiopHAGA CYPRINOIDES. S. Wood. Catal. of Crag Shells, in Ann. and Mag. of Nat. 



Hist., 1840, p. 250. 



Spec. Char. Testa ovato- oblong a, transversa, valde inaquilaterali, nitidd, lavigatd; 

 antice breviore, rotundatd; postice subtruncatd ; cardine bidentato diver gente, sinu palliari 

 minime prof undo . 



Shell ovately oblong, transverse, very inequilateral, naked, smooth, closed ; 

 anterior side the shorter, and rounded ; posterior somewhat truncate ; hinge with two 

 diverging teeth, and a small palleal sinus. 



Length, f ths of an inch ; height, \ an inch. 



Localities. Cor. Crag, Ramsholt, and Sutton. 



This species does not appear to have been at all abundant. Var. a (fig. b, c), found 

 within the walls of a Balanus, represents the right valve, which is very elongated, thin, 

 and fragile ; this is particularly inequilateral, rounded on the anterior side, somewhat 

 quadrate posteriorly ; the exterior is nearly smooth, or with merely irregular lines of 

 growth, and it is rather more tumid on the posterior side, with a sort of obtuse diagonal 

 ridge running from the umbo to the posterior part of the ventral margin ; the hinge 

 in this valve has a ledge or fulcrum for the ligament, within which is an elongated 

 tooth nearly parallel, and behind the umbo, with a compressed one diverging under 

 the anterior margin ; in the left valve are also two teeth, one of which is of an obtusely 

 triangular form, and seems to have been inserted between the two of the opposite 

 valve, while the other fitted into the depression outside the anterior tooth of the right 

 valve. Var. j3 (fig. a) is comparatively much shorter and thicker, and was found loose 

 in the sand ; the hinge area in this is broader and thicker ; the marks of the adductor 

 muscles are large and somewhat deeply impressed, and that by the mantle has but a 

 very small indentation ; the length of the larger specimen is as one and a half to its 

 height, whereas the smaller variety is scarcely longer than it is high. 



Venerupis striatula of Nyst, * Coq. Foss. de Belg.,' p. 100, pi. iv, fig. \\a, b, very 

 much resembles our shell, but it has a large and deeply-indented sinus in the mantle- 

 mark, and the shell to which he has referred his species has also the same dis- 

 tinguishing character. 



