VENERIN.E. 417 



gaping. Hinge usually composed of three diverging pri- 

 mary or cardinal teeth in each valve ; cartilage external, 

 marginal. Muscular impressions smooth, oval ; pallial line 

 sinuated. 



Animal marine, locomotive or burrowing. 



Sub-fam. VENERIN.E. 



Siphons free at their extremities. Foot lanceolate, with- 

 out a byssal groove. 



Shell ovate, sub-trigonal. Hinge with the cardinal teeth 

 triangular, and with an anterior lateral tooth. 



Genus VENUS, Linnaeus. 



Mantle-margins fringed or furbelowed ; siphons unequal, 

 separate, diverging, the branchial with a double row of 

 cirrhi, the inner one long and simple, the outer shorter, 

 furcate or stellate ; anal siphon conical, crowned with short 

 cirrhi. 



Shell thick, ovate, tumid ; valves transversely grooved or 

 lamellated, margins finely crenulated ; lunule distinct. Hinge 

 thick, tri-dentate in each valve ; primary teeth nearly equal, 

 divaricate, the apex sometimes bifid. Pallial line with a 

 short, angular sinus. 



Syn. Omphaloclathrum, Klein. Antigona, Schum. 

 Dosina, Gray. 



Ex. V. verrucosa, Linnceus, pi. 107, fig. 1. Shell, V. 

 verrucosa, fig. 1, a, 1, b. 



The shells in this genus are either verrucose or orna- 

 mented with concentric ribs or stria?, or with lamellae, or 

 they are decussated by longitudinal furrows. The species 



