26 



appearaace, the efFect of its being minutely decussated with concen- 

 tric and radiating strise, and covered ■with an exquisite thin shining 

 homy epidermis, disposed in fine concentric cords, abruptly termi- 

 nating at the posterior area. The posterior portion, accordingly de- 

 Btitute of epidermis, is very thickly rayed with ribs of short com- 

 pressed spines, as if the delicately clad surface of the shell had been 

 thus far ploughed up, as it were, into fuii'ows. 



Only two odd valves of this pre-eminently beautiful ghell were ob- 

 tained, and, singularly, in localities very remote from each other ; 

 one was dredged at the depth of forty fathoms in the Sooloo Seas, be- 

 tween the islands of Borneo and Mindanao ; the other in the Yellow 

 Sea, thirty degrees north, at one of the islands of the Korean Archi- 

 pelago. 



