OF CONCHOLOGY. 





DESCRIPTION OF A NEW SPECIES OF PISIDIUM FROM 

 CALIFORNIA. 



BY WM. M. GABB. 



P. INSIGNE, Gabb.— Plate 2, fig. 2. 



Description. — Shell minute, transverse, oval, subquaclrate, very 

 inequilateral, compressed. Anterior side produced, obliquely 

 truncated above ; posterior side regularly rounded ; beaks very 

 small, hardly projecting beyond the outline of the shell; hinge 

 delicate, the lateral teeth long and slender ; surface ornamented 

 by a few minute strise; color light yellowish-brown. 



Dimensions. — Long. *09 in. ; hit. -07 in. 



in. 



Ha.bitat.~~- From a spring at Fort Tejon ; collected by Dr. Geo, 

 H. Horn. 



Cabinet of the Philadelphia Academy. 



Remarks. — This species is more nearly allied to P. ultramon- 

 tanum, Prime, than to any other American Pisidium. It is, 

 however, not half the size, and differs markedly in outline. 



