96 CLASS I. TROPIOPODA. ORDER I. BIMUSCULOSA. 



asserted by Sowerby, that, although often found living in cavities of 

 rocks, the Venerupes are evidently not terebrating animals, like the Saxi- 

 cavce and Petricolcs ; their places of habitation being rather the result of 

 accident. Their affinity with the Venus pullastra of Lamarck, and its 

 cognate species, is now clearly established. 



The shell of Pullastra is described as being equivalve, transverse and 

 inequilateral, much shorter on the anterior side. There are three conti- 

 guous cardinal teeth, sometimes a little emarginated at the point, in each 

 valve, but no lateral teeth. The muscular impression of the mantle has a 

 large sinus ; and the ligament is external, partially concealed within an 

 elongated marginal pit. 



Examples. 



PI. LXXII. Fig. 1. 



Pullastra vulgaris, Sowerby, Genera of Shells, No. 28. 

 Venus textile, Gmelin. Lamarck. 



PL LXXII. Fig. 2. 



Pullastra literata, Sowerby, Genera of Shells, No. 28. 

 Venus literata, Linnaeus. Lamarck. 



PI. LXXII. Fig. 3. 



Pullastra papilionacea, Sowerby, Genera of Shells, No. 28. 

 Venus papilionacea, Lamarck. 

 Venus rotundata, Linnaeus. 



Family 9. CARDIACEA. 



Testa sequivalvis, cordiformis vel transversa, interdum subhians ; seepis- 

 sime costis ab umbonibus ad marginem divergentibus. Dentes car- 

 dinales plerumque duo, vel in forma vel in situ irregulares. Dentes 

 laterales aut duo, aut unicus, aut nullus. 



