PLATE XXXN.— Continued. 



OrTHOCERAS JACULtrM. 

 Page 366. 

 Fig. 12. A fragment, preserving eight air-chambei-s and a portion of the chamber of habitation. Surface- 

 markings are shown over a portion of the tube. Upper Helderberg limestone at Clarence 

 Hollffw, N. Y. 



Orthoceras molestum. 



Page 268. 

 F ig. 13. The chamber of habitation nearly entire, and a portion of five of the posterior air-chamberB, show 

 ing the regular and rapid expansion of the tube to the aperture, Upper Helderberg limesto ne 

 Clarence Hollow, N. Y. 



Orthoceras pravtim. 



Pace 255. 

 See Plates 36, 81, 112. 

 Pig. 14. An enlargement to six diametei-s of the surface of a portion of the test remaining on specimen fig. 1, 

 pi. 36, showing the character of the transverse strise. 



Orthoceras PROOERtrs. 



Page 249. 



See Plates 78 A, 79. 



Fig. 15. An imperfect individual, preserving the outer chamber nearly entire, with about thirty-six septa. 



Schoharie grit, Schoharie, N. Y. 

 Fig. 16. Septum of specimen fig. 1, pi. 78 A, showing the position and size of tUe siphunele at the septum. 

 Schoharie, N. Y. 



