APPENDIX. 369 



postice subtruncata, margine ventral! rotundata, um- 

 bonibus prominulis, lunula longe caudata. 



This species approaches very much in sculpture to 

 the C. corrugata of Adams and Keeve (' Zoology of 

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

 but differs very much in shape. The peculiar undulate 

 plications are chiefly discernible near the umbones, the 

 plicas or ribs on the lower third of the shell being 

 plain. The beaks are nearly central and prominent ; 

 the anterior extremity is somewhat produced, while pos- 

 teriorly the shell is somewhat truncate. Long, rather 

 more than inch ; lat. nearly | inch. Hob. Esquimalt 

 Harbour, Vancouver Island. (Brit. Mus.} 



UNIONID^l. 



Anodonta cognata. (Gould.) Very abundant east and west of the 



Cascades. 

 Alasmadonta angulata. (Say.) Columbia River, Fort Colville, not 



strictly in British Columbia. 



MYTILID^E. 



Mytilus trossulus. (Gould.) Abundant, rocks between tide marks. 

 californiensis. (Conrad.) Abundant, grows to an immense size, 



sought as an article of diet by the Indians along the Vancouver 



Island coast. 



Nucula lyalli. (Baird : Nov. Sp.) 



Testa ovate-triangular!, tumida, crassa, umbonibus 

 prominulis, antice breviore, subrostrata, postice declivi, 

 elonga,ta, margine ventrali rotundato, epidermide oli- 

 vacea induta, longitudinaliter utrinque costata, costis 

 fortibus, medio divaricatis ; intus margaritacea ; margine 



VOL. II. B B 



