78 NEW YORK STATE MUSEUM 



Sections which probably belong to this species have also been 

 collected in the lowest Bertie at Crossroads near Union Springs, 

 N. Y. 



Measurements. The entire length of the specimen is 135 mm, 

 that of the living chamber 79 mm, its wi'dth in the middle about 

 103 mm. Sutures in middle of mature portion of conch about 

 8 mm apart. 



Remarks. This rather incompletely preserved specimen has 

 been described chiefly on account of its interesting occurrence in 

 the Eurypterus beds of the Bertie waterlime. It is there associated 

 on the same slab with E . r e m i p e s . 



The specimen is a gerontic individual, as shown by the remark- 

 able crowding of the septa behind the living chamber. From the 

 fragments of the septate portion of the conch, and especially from 

 the rather strong divergence of the sutures, it can be inferred that 

 the conch was typically breviconic and expanded very rapidly. 



The form of the living chamber " invites comparison with 

 Phragmoceras nestor Hall, P. elliptic um Whit- 

 field, that of the curvature of the conch with P . h o y i Whitfield 

 and P. angustum Newell, all from the western Niagaran, 

 and also with P . hector Billings from the Guelph. From the 

 first-named species it is distinguished by the larger size and the 

 greater length of the living chamber along . the ventral margin. 

 It is also to be noted that the latter margin is concave in P . 

 nestor and bulging outward in P . a c c o 1 a . , All these differ- 

 ences could be attributed to differences in age, for P . n e st o r 

 could be well considered as a younger individual of P . a c c o 1 a , 

 were it not that the drawing of the type 1 showed also an extremely 

 shallow last chamber indicating old age. P. ellipticum has 

 a living chamber which, while attaining the size and general outline 

 of that of P. accola, possesses straight or, according to 

 Kindle's figure, 2 even a concave inner margin. P . h o y i has a 

 curvature very much like our species and the younger specimens 

 of P . accola may well have resembled it, but its living chamber 

 is relatively longer, and P. angustum, as described by Kindle, 

 has also an elongate living chamber and its sutures are also much 

 more and differently curved. 



1 James Hall. Account of Some New or Little Known Species of Fossils 

 from Rocks of the Age of the Niagara Group. 20th N. Y. State Mus. Rep't, 

 1867, p. 348, fig. 7. 



2 E. M. Kindle. The Stratigraphy and Paleontology of the Niagara of 

 Northern Indiana. 28th Annual Rep't Dep't of Geol. and Natural Resources 

 of Indiana, 1903, pi. 19, fig. 5. 



