PLATE XL 
Orthoceras Eriense. 
Page 274. 
See Plate 87. 
Fig. 1. The chamber of habitation apparently entire, with a portion of two of the adjacent air-chambers' 
Lake Erie shore, Hamburg, N. T. 
Fig. 2. The convex surface of a septum, from the preceding specimen, showing the central position of the 
siphuncle. 
Fig. 3. A portion of the test, enlarged two dian^ters. 
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 exterior of the air-chambers. 
Otisco, Onondaga county, N. Y. 
