394 Canadian Record of Science. 



Strophomena Kingii, on the ground that the umbones of 

 ventral valves of the former are more full, and the valves 

 themselves proportionally more convex, than those of 

 S. Kingii. 



MOLLUSOA. 



Cephalopoda. 



ascoceras costulatum. (sp. iiov.) 



Shell large, elliptic-subovate, longer than broad and 

 broadest in advance of the mid-length, the neck or 

 anterior prolongation of the body chamber being broken 

 off in the only specimen known to the writer : outline of 

 transverse section in the broadest part apparently ellipti- 

 cal, the dorsum and venter being compressed and the 

 sides slightly expanded. 



Surface transversely but rather finely ribbed, the ribs 

 averaging from seven to nine in the length of one centi- 

 metre, and rather closer together near the aperture than 

 in the more expanded portion. 



Sigmoidal septa apparently three in number, though 

 their distances apart, on the dorsum, cannot be ascer- 

 tained. The suture, however, which forms the line of 

 demarcation between the decurrent extremity of the body 

 chamber and the septate portion, on both sides, is clearly 

 defined. It shows that the body chamber extends as far 

 backward as to within about half an inch from the 

 blunted pointed posterior end, that it is dilated or pro- 

 duced laterally, towards the dorsum, for a short distance 

 posteriorly, and concavely constricted for a much longer 

 distance anteriorly. 



Black Island, 1 Swampy Harbour, Lake Winnipeg, D. B. 

 Uowling and L. M. Lambe, 1890 : a badly preserved cast 

 of the interior of the shell, with one side much worn, but 

 with portions of the test preserved on both the venter 

 and dorsum. 



i A small island close to, but a little to the west of, Beren's or Swampy Island. 





