324 



has dredged it in Manger fiord on the coast of Finraark ; 

 but it appears on the whole to be a southern form, 

 ranging from Vigo along the Lusitanian shores east- 

 ward to the Mediterranean and ^Egean, and westward 

 to Madeira and the Canaries, at depths between 4 and 

 95 fathoms. 



It bears the following names, besides those given by 

 Montagu: Venus pumila, Lamarck, V. Cyrilli, Scacchi, 

 Cytherea apicalis, Philippi, Cytherea minuta, Brown, 

 and probably Venus (Cytherea) occitanica, Recluz. 



*** Mantle open in front, and forming at the posterior side 

 two more or less elongated tubes. 



Family XIII. VENE'RID^E, Leach. 



BODY nearly orbicular, oval, oblong, or globose : tubes pro- 

 duced, cylindrical : gills unequal : foot tongue-shaped and 

 large, adapted for burrowing in gravel, sand, or mud. 



SHELL equivalve, triangular, rhomboidal, or globular ; va- 

 riously sculptured, or almost smooth : beetles incurved, and 

 turned towards the anterior side : liyament external, placed on 

 the larger side of the shell : liinye strong, furnished with three 

 or four cardinal teeth in each valve (one genus having two only 

 in the left valve), some of which are cloven or double, and an 

 obscure and ridge-like lateral tooth on the posterior side : 

 pallial scar deeply sinuous : muscular scars oval and distinct. 



The deep sinuation of the pallial scar will always 

 serve to distinguish the Venerida from any of the im- 

 mediately preceding families. It denotes also a cor- 

 responding difference in the structure of the animal, the 

 siphonal tubes being extensile and issuing from a sheath 

 or fold of the mantle in this family, instead of sessile 

 or short as in the other families. The form of the 

 shell in the typical genus Venus is similar to those of 

 Cyprina and Circe ; but the lateral teeth are less distinct, 



