LUCINA. 407 



primary teeth, and two lateral teeth in each valve ; ligament 

 usually external. Muscular scars strongly marked, the 

 anterior elongated; pallia! impression simple. 



Syn. Phacoides, Blainville. 



Ex. L. Jamaicensis, Spengler, pi. 113, fig. 4, 4, a. 



The species of Lticina have a wide geographical range, 

 being found on the sands along the shores of most countries 

 of the world. The shells differ considerably in form and 

 sculpture, being either globose or lenticular, reticulated, 

 ribbed, or laminated. 



Species of Lucina. 



annulata, Reeve. gemma, Reeve. 



argentea, Reeve. Jamaciensis, Spengl. 



aurantia, Desh. lactea, A. Adams. 



bicornis, Reeve. Pensylvanica, Linn. 



borealis, Linn. pisum, Reeve. 



columbella, Lam. simplex, Reeve. 



dentifera, Jonas. speciosa, Reeve. 



emarginata, Barth. sulcata, Reeve. 



funiculata, Reeve. virgo, Reeve. 



Sub-gen. cyclas, Klein, not Bruguiere. 



Shell with the surface of the valves obliquely and circularly, 

 or divaricately striated. 



arcuata, Mont. eburnea, Reeve. 



digitalis, Lam. gibba, Gray. 



digitaria, Linn. ornata, Reeve. 

 divaricata, Linn. 



Sub-gen. codakia, Scopoli (Chama, Mart., not Linn. Lentil- 



laria, Schum.). 



Shell compressed, with the surface of the valves radiately 



