PLATE LXXVIII. 



OUTUOCERAS OBLIQUtJM, 0. VASTATOR, n. Sp.* 

 I'age H3. 



Fig. 1. A fragment, retaining a large portion of the chamber of habitation, arid about twenty adjacent 

 chambers. (Ventral view?) 



Fig. 2. A septum from tigure 1 showing the position of the siphuucle, and the areola surrounding its inser- 

 tion in the septum. 



Fig. 8. Lateral view of another fragment pi-esenting the extreme, but apparently normal, obliquity of the 

 septa. 



Fig. 4. A small septate portion of an individual referred to this species. The specimen is flattened in a 

 dorso-ventral direction, destroying the cun'atui-e of the septal margins over the doi-sal and 

 ventral sides. 



Orthoceras luxum. 



Page 'i44. 



See Plates 35, 76, 77, 78 B, 81, 112. 



Fig. 5. A fragment of this species consi<lerably compressed. This figure represents a common condition of 



the specimens. Schoharie, N. Y. 

 Fig. 6. A septum of the preceding specimen, showing the areola surrounding the siphuncle, and extending 



to the ventral side. 

 Fig. 7. Longitudinal section of a distorted fragment, preserving some traces of the siphuncle. Clarks- 

 vUle, N Y. 



* The name O. obliquum having been preoccupied by Eichwald in 1860, the name of this species is here 

 changed to 0. vastator. See corrections and Addenda. 



