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cave, sutures having usually ventral and dorsal saddles and lateral 

 lobes. This last statement is true of all the forms having the gyro- 

 ceran mode of coiling, but not of those which have the closer nau- 

 tilian form. In these there is a slight dorsal lobe and a different 

 form of the paranepionic whorl which may eventually lead to their 

 generic separation. 



The type is Barrandeoceras (Naut.) natator, sp. Billings. 

 Barrandeoceras Minganense. 



Loc, Mingan Islands. 



There is a specimen from the Chazy limestone of the Mingan 

 Islands in the collection of the Museum of the Geological Survey 

 at Ottawa which has very similar characters to those of Barrandeo- 

 ceras natator, but is distinct in some of its characters. The living 

 chamber is short and, if complete, about a quarter of a volution in 

 length. It is free and in section is compressed oval, the abdomen 

 broader than the dorsum, but the centro-dorsal diameter is longer 

 than the transverse. 



The siphuncle is nearer the centre, being ventrocentren. The 

 neanic, or perhaps an ephebic stage has slight annulations or raised 

 lines of growth, judging from the marks on the section. This is 

 labeled as coming from the white limestone of Large Island. 



There is no impressed zone at any stage observed. The ephebic 

 stages have a whorl similar to that of Barrandeoceras convolvans in. 

 the neanic stage, but the abdomen is broader. 

 Barrandeoceras convolvans. 



Lituites convolvans, Hall {Pal. cf New York, i, p, 53, PL xiii, 

 Fig. 2). 



Loc, Watertown, N. Y. 



The specimen figured by Hall has in the ephebic stage sutures, 

 with slight dorsal lobes. This, however, may have been a mistake 

 in drawing or an abnormal individual variation. A specimen in 

 the Museum of Comparative Zoology from the same locality, ex- 

 hibiting the form of the whorl and the sutures of the ephebic stage, 

 does not have such lobes. 



The characteristics otherwise are so close to Hall's description 

 and figure that, in spite of this and the supposition that the siphun- 

 cle was ventral, I have referred this and a suite of sections of the 

 same to his species. 



The whorls are variable in the coiling, and in some specimens 

 are plainly not in contact at any stage. In others the neanic volu- 



