451 
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.) xatator, 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 (Pa/. 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 Zodlogy 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- 
