APPENDIX. 367 



mis, which is striated transversely. The ventral margin 

 is gaping and flexuous. This species resembles consi- 

 derably the L. navicula of Adams and Eeeve (' Zoology 

 of the Voyage of the Samarang '), from the Sooloo Sea, 

 and might be taken for a very large specimen of it, 

 and, indeed, is considered to be so by Mr. Adams him- 

 self, who informed me he had taken identically the same 

 species, as to size, &c., from the seas of Japan. Besides 

 the size, habitat, and place of abode, this species differs 

 from L. navicula in the form of the anterior extremity 

 of the shell and the more gaping ventral margin. 

 Owing to the peculiar place of abode (holes in the 

 rocks), it varies considerably in size and form ; but in 

 all the specimens which I have seen, ten in number, it 

 does not vary in the produced anterior extremity. The 

 striae seen on the surface of the epidermis do not appear 

 to extend from it to the shell underneath. It lodges 

 always in holes in the rocks, from which it is very dif- 

 ficult to extract it, without breaking it ; for it would 

 appear to take up its abode in a small hole, enlarging 

 it as it increases in size itself. The substance of the 

 shell, without being very thin, is exceedingly brittle ; 

 and few specimens were brought over without being- 

 cracked across in various places, apparently in the act 

 of drying. The ossicle covering the front of the inter- 

 nal cartilage is strong and well developed. The length 

 of a moderate-sized specimen is about 3 inches, of a 

 large specimen 4-^ inches ; the breadth from the beaks 

 to the ventral margin is about 2 inches and 2^ inches. 

 Hob. Holes in rocks in Esquimalt Harbour, Van- 

 couver Island. (Brit. Mus.} 



