424 • NEW YORK STATE MUSEUM 



Canada that even approaches this in the distance of the septa. The 

 species from the Black river Hmestone of Henderson bay, Jefferson 

 CO. N. Y. which has been described by Hall as E . g e m e 1 - 

 1 i p a r u m — under the assumption that foreign cephalopods which 

 had entered the extremely wide siphuncle, were young ones — pos- 

 sesses cameras of exactly the same depth and like gigantic dimen- 

 sions, but its siphuncle is so large (greatest diameter 60 mm), that 

 the phragmocone is reduced to a narrow ring. On account of the 

 latter fact we have refrained from identifying our form with this 

 remarkable species from the Black river beds. If they are not 

 identical their closest relationship can not be doubted. On account 

 of the absence of an endosipholining and the restriction of the length 

 of the septal necks to that of one interseptal space, we have referred 

 this species to the genus Endoceras. 



Endoceras montrealense Billings (sp.) 



Plate 9, figure 8 

 Orthoceras montrealensis Billings. Can. Nat. & Geo!. 1859. 



4:363; P- 361, fig. iic-e 

 Orthoceras sordidum (Billings) Whitfield. Am. Mus. Nat. Hist. 



Bui. 1890. 3:34, pi. 2, fig. 4 



Professor Whitfield has referred an orthoceraconic form from the 

 Fort Cassin beds, characterized by very closely set septa and mar- 

 ginal siphuncle to Orthoceras sordidum Billings, a species 

 from the White limestone of the Mingan islands. He argues that 

 O . d e p r e s s u m and O. montrealensis Billings are prob- 

 ably only variations of that species, since in examples of different 

 sizes of his material the septa vary in their distances. 



We have received some additional material of this Fort Cassin 

 form through the kindness of Professor Perkins. This has allowed 

 the cutting of sections and thereby cleared up the doubt as to the 

 character of the siphrmcle [see text fig. 8] . The latter suggested at 

 once, by its relative size, that this supposed representative of O . 

 sordidum should be more properly identified with O . 

 montrealense which differs from O. sordidum less by 

 the relative distance of the septa than by the relative size of the 

 siphuncle. In the latter feature however as well as in the rate of 

 growth of the conch, the specimens from Fort Cassin agree exactly 

 with O . montrealense.^ The further fact that the type of 



^Billings states under O. sordidum, that it differs from O. mon- 

 trealense in being a more slender species and having the siphuncle 

 smaller. It is exactly in these characters that our material also differs from 

 O. sordidum. 



