PLATE XL 



Orthoceras Eriensb. 



Page 274. 



See Plate 87. 



Fiy. 1. The chamber of habitation appai-ently entire, with a portion of two of the adjacent air-chambers* 



Lake Erie shore, Hamburg, N. Y. 

 Fig. 3. The convex Burface of a septum, from the preceiing specimen, showing the central position of the 



siphuncle. 

 Pig. 3. A portion of the test, enlarged two diameters. 

 Fig. 4. A fragment of the septate portion of an individual referred to this species. The specimen is extremely 



compressed, and preserves no surface-markings as evidence of the position of the siphuncle. 



A parasitic, branching Bryozoan extends over a portion of the extei-ior of the air-chambers. 



Otitoo, Onondaga county, N. Y. 



