350 APPENDIX. 



snails with spiral shells ; and a considerable num 

 ber on the outward coast, which is washed by the 

 ocean. Here are several species of the genera Murex, 

 Fusus, Buccinum, Mitra, Trochus, and Turbo. Fur 

 ther, there are found here a large Fissurelki, and 

 six species of a genus which, from its simple, un 

 wound shell, would be immediately taken for a 

 Patella ; the creature, however, closely resembles 

 the Fissurella, with the difference that only one gill 

 is visible in the fissure over the neck. It is re 

 markable, that on the whole north-west coast of 

 America down to California, no Patella, only ani 

 mals of the genus Acwcea, were to be met with. Of 

 the Chiton genus, six species were observed ; in one, 

 the side skin covers the edges of the shell so far as 

 to leave only a narrow strip of it visible down the 

 back ; in others, the shell is entirely concealed un 

 der the external skin. It is worthy of remark, that 

 these latter, as well as one similarly formed, found 

 in California, attain the considerable length of eight 

 inches. A third kind, to be reckoned among this 

 subdivision, Pallas obtained from the Kurile Islands, 

 and has described it as Chiton amiculatus. 



Among the Acephala are to be named a large 

 Cardium, also found on the Californian coast ; Mo- 

 diolus, two species; Mytilus ; Mya, two species; 

 an3 Teredo palmulatns : the latter, which is brought 

 here by the ships, is very mischievous in the har 

 bour, and attains to the length of two feet. In 

 this species are comprehended three Asddice, of dif- 



