PLEISTOCENE FOSSILS. 257 



Buceinum glaciate. Linn. 



Fossil Riviere-du-Loup; Montreal; Anticosti; Labrador (Packard); 

 Black Point, N.B. (Matthew). 



Recent Murray Bay ; Little Metis ; Alaska (Dall) ; Greenland, 

 and Arctic seas generally. 



This shell has the aperture somewhat like that of ciliatum, and a 

 very peculiar sculpture of spiral striae with intervening bands marked 

 vvitli finer striae. It has also a carina angulating the body whorl, and 

 sometimes more than one. In the latter case it passes into B. Grcen- 

 landicum, Hancock (not Chemnitz) or B. Hancocki Morch. The 

 ordinary variety is most common in the modern Gulf, the latter in 

 the arctic seas and in the Pleistocene. This shell, usually much 

 decorticated, is the most common Buceinum in the Pleistocene of 

 Montreal. (See figures, plate I.) 



Buceinum plectrum. Stimpson. 



Fossil Riviere-du-Loup ; rare. 



Recent Murray Bay ; Portland, Maine (Stimpson) ; Behring's 

 Straits (Stimpson) ; Alaska (Dall). 



This may be a variety of the preceding species, but can be distin- 

 guished from it and grows to a larger size. It has the sculpture of 

 B. glaciate with the aperture of B. undulatum. Recent and fossil 

 specimens are quite similar. 



The northern Baccina are involved in so much confusion that I 

 have made them a subject of special study, and have sedulously 

 collected all the forms recent and fossil. I have been very much 

 aided in this by the abundance of specimens of the more arctic forms 

 at Riviere-du-Loup, and the occurrence of most of them recent at 

 Murray Bay and Tadoussac, and I feel confident that the names given 

 in this list represent forms actually occurring as distinct in nature, 

 though some of them may not be distinct specific types. I believe, 

 however, that B. ciliatum, B. glaciale, B. undulatum, B. tenue and 

 B. Gr&nlandicum, are probably entitled to this rank. The others 

 appear to me, on comparison of large numbers of specimens, to graduate 

 into one or other of the above forms. 



I have given in the engraved plate representatives of the more 

 critical forms, which will enable them to be recognized. 



In the drift the Buccina often part with their outer coat of 

 prismatic shell, and in this decorticated state are very difficult to 

 determine. 

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