LABIOSA. 385 



Genus VANGANELLA, Gray. 



Shell transversely oblong, thin, compressed, covered with 

 a hard, polished epidermis ; beaks central ; valves rounded 

 in front, rather produced and tapering behind, strengthened 

 internally by two diverging, elevated ribs; hinder gape 

 moderate. Hinge with the cardinal tooth of left valve 

 folded together, of right valve small, separate ; lateral teeth 

 short, small, close to the cartilage-pit ; ligament sub-exter- 

 nal, marginal, not separated from the cartilage by any shelly 

 plate ; cartilage in a large, elongate, shallow, triangular 

 pit on the upper part of the hinder internal rib. 



Syn. Kesania, Gray. 



Ex. V. Taylorii, Gray, pi. 1 02, fig. 2, 2, a. 



The Resania lanceolata of Gray is founded upon the 

 same shell as the Vanganella Taylorii. " This genus 

 combines the form and internal appearance of a Solen 

 (SUiqua) with the hinge-characters of a Mactra. The 

 position of the cartilage-pit and the internal ribs at once 

 separate it from Sjnsula." (Gray.) 



Genus LABIOSA, Schmidt. 



Shell oblong, marked with an oblique posterior ridge, 

 largely gaping and reflexed behind. Hinge with the lateral 

 teeth distinct, the anterior oblique, near the cartilage-pit; 

 ligament sub-external, marginal, not separated from the 

 cartilage. 



Syn. Anatina, Schum., not Lam. Cypricia, Gray. 

 Cryptodon, Conrad. 



Ex. L. anatina, Spengler, pi. 102, fig. 3, 3, a. 



