PLATE XLII. 



OaXHOCEBAS OBOTALUM. 



Page !96. 



See Plates 82, 113. 



Pig. 1. A porUon of the chamber of habitation, showing the absence of annalations near the aperture, and 

 the strong, lamellose, striate surface of the internal mould. Schoharie county, iV. T. 



Fig. 3. A specimen similar to the preceding, with the annulations more prominent, and slightly oblique. 

 PraU's falls, N. T. 



Fig. 3. A fragment somewhat compressed, showing the marked annulations, and the depth of the air- 

 chambers. Cazenovia, N. T. 



Fig. 4. A more slender sjiecimen, showing the amount of compression, and the obliquity of the annulations, 

 with the septal sutures intersecting them by planes oblique to the axis of the tube, and to the 

 direction of the annulations. Cazenovia, N. T. 



Fig. 5. A small, septate fragment, preserving the cbai-acteristic, line, longitudinal strise over the exterior of 

 the tube. Hamilton, N. Y. 



Fig. 6. The chamber of habitation nearly entire, showing the absence of annulations near the aj^erture, and 

 a jwrtion of a broad retral curve in the annulations over one side. 



Fig. 7. A fragment showing the increase in the distance and prominence of the annulations from the apex 

 toward the outer chamber. Otiseo Lake, If. Y. 



Fig. 8. A compressed fragment, exhibiting the same charactei-istics as the preceding specimen. Hamil- 

 ton, N. Y. 



Fig. 9. A lateral view of the same, showing the amount of compression. 



Fig. 11. A portion of the surface enlarged from specimen fig. 5, showing the fine, regular, longitudinal 

 strix. Two of the septal sutures are shown in the upper furrow. 



Fig. 12. A fragment of a large individual with more distant annulations. Qenegeo, Livingtton county, iV. Y. 



Obtboceras C.£LAHEN. 



I'age 298. 

 See Plates 43, 82, 113. 

 Fig. 10. An imperfect specimen, retaining portions of the test, and showing about twenty annulations. North 

 Bristol, Ontario county, N. Y. 



