QUEEN CHARLOTTE ISLANDS. 199 B 



tolerably well defined in the umbonal region, but becomes obsolete 

 in the middle of the shell. Lunule none ; lunular region abruptly and 

 obliquely compressed or inflected. 



Surface marked by coarse, crowded and irregularly disposed, concen- 

 tric wrinkles or raised striae. As viewed under an achromatic micros- 

 cope, with an inch and a half objective, the shell is seen to be covered 

 in places with an exceedingly minute, angular and irregular network 

 of raised wrinkles and radiating striae. 



Colour : — Dark rusty-brown on the exterior of the valves (possibly 

 due to the ferruginous nature of the mud or sand in which it lived), 

 whitish on the beaks and umbones. Interior, porcellanous white. 



Dimensions of the only specimen collected: — Length, 10 lines - 

 height, scarcely 7 ; thickness, 5 lines. 



Locality : — Virago Sound, in from 8 to 15 fathoms. One fine speci- 

 men, the largest known, perfect and well-preserved on the outside, but 

 with the interior of the valves much eroded and exfoliated, and the hinge 

 teeth badly broken. 



This well-marked and very distinct species has long been known to 

 Mr. "W". H. Dall, whose M. S. name for it has been adopted here. The 

 specimens in Mr. Dall's possession are from Alaska and Monterey, so 

 that the species appears to have a wide range on the west coast of 

 North America. 



Tellimya tumida, Carpenter. Dolomite Narrows, four good specimens. 



Mytilus edulis, Linnaeus. Dolomite Narrows, &c. 



Mytilus Californianus, Conrad. Beach in Houston-Stewart Channel. 



Modiola modiolus, Linnaeus. Low-water to 10 fathoms, common. 



Crenella decussata, Montagu. Virago Sound, in from 8 to 15 fathoms. 

 A single, very large example which measures nearly three lines in 

 length by two and a half in height. 



Aocincea septentrionalis, Middendorf, var. subobsoleta, Carpenter. Mouth 

 of Cumshewa Harbour, in 20 fathoms, abundant and alive ; also 

 Houston-Stewart Channel, north of Prevost Island, in 15 to 20 

 fathoms, where many specimens were obtained. At the Queen 

 Charlotte Islands only the smooth form of this species has been 

 observed. 



Nucula tenuis, Montagu, var. lucida, Gould. Virago Sound, in 8 to 15 

 fathoms, several living specimens. 



Nucula (Acila) Lyalli, Baird. With the preceding; also channel 

 opposite Seal's Head Island, in TO fathoms. 



