SILIQUA. 345 



Species of Citltelhis. 



albidus, Adams and Beeve. maximus, Gmel. 



Californianus, Conr. subteres, Conr. 



cultellus, Linn. 



Genus SILIQUA, Miihlfeldt. 



Siphons elongate, large, united, covered with a hard epi- 

 dermis. 



Shell transversely oblong, curved, covered with a polished 

 epidermis, compressed, rounded and gaping at the ends, 

 valves strengthened internally by an elevated transverse urn- 

 bonal rib. Hinge nearer the middle than the anterior end, 

 three compressed primary teeth in each valve. Pallial line 

 with a short, rounded sinus. 



Si/n. Leguminaria, Schum. Aulus, Oken. Machoera, 

 Gould. Leguminum, part, Chem. 



Ex. S. radiata, Linnmis, pi. 93, fig. 3, 3, a. 



The species of Siliqua exhibit a very extended range in 

 their geographical distribution, examples occurring along the 

 shores of Sitka, Ochotsk, Newfoundland, and Behring's 

 Straits, as well as on the tropical shores of India and the 

 China Seas. Fossil species are found in the Upper Green- 

 sand of France and Britain. 



Species of Siliqua. 



costata, Say. polita, Wood. 



lucida, Conr. radiata, Linn. 



media, Sow. scalprum, Gould. 



minima, Gmel. squama, Blainv, 



Nuttallii, Conr. violacea, Desh. 



