OF CONCHOLOGY. 305 



and crowded along the margins of the mantle lobes, and on the 

 tentacles. The inner surface differs but slightly, being only 

 much paler centrally and unclouded. 



Length, one inch. 



Habitat. Tahiti. 



Remarks. There is little doubt but that the branchiae in this 

 genus are immersed in the surface of the mantle lobes, radiating 

 in lines from the body, as in genus Placohranehus. 



Ely'sia grandifolia, JE. punctata and JE. coerulea, (Kelaart) 

 inhabiting Ceylon, belong to the above genus. The provisional 

 name, Hydropsyche, proposed for the genus by Dr. Kelaart, 

 being pre-occupied, the above •vvill take precedence. 



