131 



^noufJi harbour, where we never obferved the Venu^ Vir- 

 ginea: it is alfo not unfrequent on the fouth coaft of 

 Devon. A variety of this fliell is probably the V. Rliom- 

 boidcs of the Britijli Zoology. 



■* 20. 



Peaunculus truncatus. Da Cojla p. 195 ? Sulcata, 



V. with a ffrong, thick, fub orbicular, fubangulated, 

 flattifh fhell, with concentric ridges; the furrows or fulci 

 broader than the elevated parts, and both become nearly 

 obfolete at the fides and towards the beak, where it is only 

 •wrinkled: the colour is white, but when alive is covered" 

 with a very thick, dufky-brown epidermis, fo very opaque 

 that the colour of the fliell is not to be feen: umbo very 

 prominent and Lirge, turning a little to one hde ; beneath 

 which is a lanceolate, cordiform deprefTion ; the cartilage 

 flope is alfo depreffed, and is much more flrait than 

 on the oppofitefide ; the exterior margin is rounded. Ti^e 

 infide is white, fmooth, and glofiy at the margin ; tlie mid-' 

 die dull, yellowifh, and appears rough when examined 

 with a glafs ; the edge crenated ; hinge remarkably fiiong; 

 teeth large and prominent ; in one valve three teeth, the 

 middle one much larger than the others, with a deep ca- 

 vity on each fide, into which the two teeth of the other 

 valve lock: it has no cicatrix, but on each fide isa kinated 

 depreflion, marked with four or five femi-circular ridge.'v 

 to which the ligaments of the animal are fixed for the pur- 

 pofe of clofing the flTell. Length feven-eighths of an 

 inch; breadth nearly the fame. 



S 2 We 



