198 B GEOLOGICAL SURVEY OF CANADA. 



Lucina tenuisculpta, Carpenter. Virago Sound, in 8 to 15 fathoms, 

 five small, living specimens. 



Cryptodon flexuosus, Montagu. Dixon Entrance, in 111 fathoms, three 

 perfect specimens. 



Cryptodon serricatus, Gould. With the last ; also mouth of Cumshewa 

 Harbour, in 20 fathoms, and Virago Sound, in from 8 to 15 

 fathoms ; one living shell from each of these localities. 



Diplodonta orbella, Gould. Mouth of Cumshewa Harbour, in 20 fathoms, 

 plentiful, but mostly single valves ; Houston-Stewart Channel, in 15 

 to 20 fathoms, one dead but perfect shell. 



Kellia suborbicularis, Montagu. Dredged, living, at several localities. 



Turtonia minuta, Fabricius. Virago Sound, in from 8 to 15 fathoms, 

 one large, single valve. 



Lepton rude, Nov. Sp. 



" Lepton rude, Dall" M. S. 



Fig. 2. Lepton rude, left valve, nat. size. 



Shell rather small, equi valve, inequilateral, tumid, but not quite as 

 thick as high, most swollen on the postero-lateral and antero-lateral 

 umbonal slopes, depressed in the middle, the depression extending 

 from the beaks to the ventral margin ; test thin and fragile. 



General outline subtrapezoidal, length much greater than the height 

 base concavely and shallowly emarginate; superior border broadly 

 compressed convex, sloping gently downwards posteriorly, and rather 

 more rapidly so in advance ; posterior and anterior ends subtruncate 

 more or less obliquely above and rounded below ; posterior side some- 

 what longer than the anterior, and rather more pointed at its extremity 

 below. Umbones broad and depressed ; beaks compressed laterally, 

 eroded, moderately prominent, curved forwards, and placed a little in 

 advance of the middle. Posterior area ill-defined, indicated obscurely 

 by an oblique and abrupt compression of the valves above and behind a 

 rounded ridge or swelling, which runs in the direction of a line which 

 might be drawn from the hinder side of the beaks to the posterior 

 termination of the ventral margin. This ridge or prominence is 



