190 



Woolwich shells are ovato-transverse, and marked with very small trans- 

 verse striae, indicating the stages of growth. They have three teeth at the 

 hinge, and two compressed lateral teeth in one valve, with grooves for 

 their reception in the other valve. Like the French fossil shells of this 

 genus, the Woolwich also are entirely white, being without epidermis or 

 animal matter. 



Having obtained a mass of shells of this genus, imbedded in py- 

 rites, from the Isle of Wight, I was surprised at finding that their 

 lateral teeth, like those of the Mactra solida, were transversely grooved, 

 the penetrating teeth on the out, and the receiving teeth on the in- 

 sides. 



Plate XIII. Fig. 5, represents the valve which is furnished with the 

 penetrating grooved lateral teeth, from the Isle of Wight. 



CXVIII. Venericardia. An equivalved, inequilateral bivalve, ribbed lon- 

 gitudinally on the outside, with two thick hinge-teeth, disposed obliquely, 

 and in the same direction. 



In some species, deserving, perhaps, as Lamarck observes, to be con- 

 sidered of another genus, there is but one tooth on one valve, and two 

 diverging teeth on the opposite valve. 



These shells are strongly characterized, by their having longitudinal 

 ribs, as in the cockles and scallops. They are marine shells, and have 

 two muscular impressions. 



The most beautiful species of this genus is V. planicosta, a remarkably 

 thick shell, obliquely cordated, with flat smooth longitudinal ribs, and which 

 Lamarck describes as being sometimes three inches and a half in length. 

 The shells of this species are found in the neighbourhood of Paris, but are 

 there but small. At Piedmont, and in the neighbourhood of Florence, 

 they are found of the largest size : one specimen 1 have, which mea- 

 sures full four inches and a half. These fossil shells are found of a very 

 handsome size on the Hampshire coast; Mr. Holloway, of the Custom- 

 house, Portsmouth, has kindly favoured me with specimens from Selsea, 

 one of which measures nearly three inches and a half in width. 



