240 THK ICK A(iK L\ CANADA. 



Creiidlti [fhiiiilnlii. Totten. 



TliiH HpuuicH, wliifli is at present quite comiiiitn in the (iulf Si. 

 rwvwreiicc, is indieated in iny formerly publislieil lists as a Montioal 

 fossil ; but I have mislaid tiie specimens, and cannot therefore now 

 repeat the comparisons with the recent siiells. It is prol»al)ly (', Jttlia 

 of Kahrieins. 



According to Mr. Whiteavcs tin's is (jnito distinct from C. tlcruxsata, 

 Montagu, both being found living in (iuspc. 



Nucnld fcuiiiM. Montagu. 



Fossil — Leda clay, Montreal; Saco (var. iiijfdfn) ; Riviere-du-Loup, 

 IJay de Ciuileur (Mattiiew)? (ircen's Creek, Ottawa River, 



Recent —North Shore ; also (iulf St. Lawrence to (lasp.- (Whiteavcs) ; 

 Little Metis (type and vur. iiijliitd ; also European coasts and llritish 

 Columbia. 



N. expanxa. Reeve. 



Fossil — Leda clay and boulder-clay, RIviero-dii- Loup ; Saco; 

 \Vestl)rook, Duck Cove, St. John, N. li. (Matthew) ; Pakenham '! 



Recent — Labrador (Packard); Murray llay; Little Metis; Arctic 

 seas. 



I doubt if this is not a large and well-developed northern form of 

 X. tenuis. 



AT. antiqua. Miirch. From Leda clay of Maine ; seems to be a variety 

 of the last. 



Leda pernula. Muller. 



Fossil — Leda clay, Rivicrj-du-Loup ; New Richmond; New Rruns- 

 wiek (Matthew) ; I'ortland ; Saco ; Lawlor's Lake, N.R. (Matthew), 



Recent — Little Metis ; Kamouraska ; Arctic seas and south to New 

 England. 



This shell occurs very abundiintly at Riviere-du-Loup ; and the 

 specimens found there show that no specific line can be drawn between 

 the forms known as peniuUi, hiicr(tl<i (Steenst. ), fciinisn/rd/d, Could, and 

 Jackmnii, Could. Slender and flattened varieties are pernnia and 

 tenumdcata, shorter and more tumid forms are huccata ; and specimens 

 decorticated so as to show tiie origin of tlie hinge teeth are Jacksonl. 

 Comparison of specimens from Creenland, Norway, Labrador, the 

 Gulf St. Lawrence, and New England, confirms this conclusion. 



