480 galeommidjE. 



chloroleuca, Desk. machrochisma, Desh. 



formosa, Desk. paucistriata, Desh. 



indecora, Desh. polita, Desh. 



inflata, Desh. splendida, Desh. 



Layardi, Desh. Turtoni, Sow. 



Genus SCINTILLA, Deshayes. 



Animal unknown. 



Shell transversely ovate, obtuse, somewhat gaping at 

 both sides, tumid, thin, very shining, destitute of epidermis ; 

 superior margin usually straight ; inferior parallel, and never 

 emarginate in the middle. Hinge narrow, short ; in the 

 right valve a single, porrect, uncinate cardinal tooth ; in 

 the left two, unequal, approximate, divaricate teeth, the in- 

 ternal the larger : a lateral tooth, short, conical, or sub- 

 quadrangular, on the hind side near the hinge, received into 

 the follicle of the bifid tooth in the other valve ; ligament 

 internal, short, broad, thin, affixed in a narrow, oblique 

 groove in each valve. Pallial impression entire. 



Ex. S. Philippinensis, Deshayes, pi. J 1 5, fig. 4, 4, a. 



One species of this genus appears to have been known 

 to M. Quoy, and was described by him under the name of 

 Psammobia vitrea, but was said to have two cardinal teeth, 

 and an external ligament. The animal, according to him, 

 approached that of Galeomma, and is certainly far from 

 being a true Psammobia. The shells of the genus Scin- 

 tilla have a peculiar appearance, which distinguishes them 

 from all other known genera. They have an affinity on 

 one side with Erycina, as reconstructed by M. Eecluz, 

 and on the other side with Galeomma, and are, appa- 

 rently, intermediate between the groups. There is a singu- 

 larity in the external appearance of some of the species, 



