APPENDIX. 369 
postice subtruncata, margine ventrali rotundata, um- 
bonibus prominulis, lunula longe caudata. 
This species approaches very much in sculpture to 
the C. corrugata of Adams and Reeve (‘ 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 
plicee 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 2 inch; lat. nearly $ inch.—Hab. Esquimalt 
Harbour, Vancouver Island. (Brit. Mus.) 
UNIONIDZ. 
Anodonta cognata. (Gould.) Very abundant east and west of the 
Cascades. 
Alasmadonta angulata. (Say.) Columbia River, Fort Colville, not 
strictly in British Columbia. 
MYTILID. 
Mytilus trossulus. (Gould.) Abundant, rocks between tide marks. 
— caljforniensis. (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 ovato-triangulari, tumida, crassa, umbonibus 
prominulis, antice breviore, subrostrata, postice declivi, 
elongata, margine ventrali rotundato, epidermide oli- 
vacea induta, longitudinaliter utrinque costata, costis 
fortibus, medio divaricatis ; intus margaritacea ; margine 
VOL. Il. BB 
