PLATE XCV. 



Ctrtoceras liratdm. 



I'agc 364. 

 Fig-. 1. Lateral view of the 8pecimoii, Bhowing' the curvatui-e of the tube, the septate apical portion, ami the 

 regular, U>ngitu<linal fun-ows ornamenting the shell. Ooniatite limestone. MarceUus, iVi T. 



GOMPBOOERAS TUMIDUU. 



Phgo SSI. 



See Plate 93. 



Fig. 2. The apical portion of an individual, showing the depth of the air-chambers and the enlargement of 



the tube. Cliemung group. Ithaca, N. T. 

 Fig. 8. An imjierfect fragment, which has been much disturbed by compression, doubtfully referred to 



this species, but occurring in the same association with the preceding. Chemuug group. 



It?utca, y. T. 

 Fig. 4. A compressed individual, showing the branches of a parasitic Bryozoan on the surface of the tube. 



Chemung group. CascadilUi Creek, Ithaca, N. T. 

 Fig. 5. A fragment preserving its normal proportions, and showing the ventricose chamber of habitation 



and attenuate apex. Upper Chemung group. New Albion, Cattaraugus county, N. T. 

 Fig. 7. A specimen much compi-essed, but showing the attenuate apex and subglobose chamber of habita- 

 tion. Several branches of two species of parasitic Bi-yozoans are attached to the grand 



chamber. Chemung group. Ithaca, N. Y. 



GOMPHOCERAS PINQtTE. 



Page 346. 



See Plate 94. 



Fig. 6. The apical portion of an individual which has been disturbed by compression, but refeired to this 



species on account of its association and the depth of the air-chambers. Hamilton group. 



North of Caze7iovia, N. Y. 



CraTOCEBAS (GoMPHOCERAS) PORMO80M. 

 Page 362. 

 Fig. 8. The chamber of habitation, showing the surface ornaments of the tube, which become in part obso- 

 lete near the apertui-e. The lines in the figure, crossing the hiatus in the margin of the aper- 

 ture, do not appear in the specimen. Uamilton group. Dresden, N. Y. 

 Fig. 9. An enlargement of the surface, showing more minutely the characters of the ornamentation. 



GOMPHOOERAS LUNATUH. 

 Page 341. 



Fig. 10. The chamber of habitation, with sevei'al attached aii'-chambere. 



I'ig. 11. A septum of the same, showing the position of the siphuncle and the areola around its insertion. 



Fig. 12. The apical portion, which is a continuation of specimen fig. 10, showing the enlargement of the 

 lube and the variation in the depth of the air-chambera. Portions of the test, showing the 

 ornamentation of the sui-face, the ci'cnulations and ventral furiow, are not represented in 

 the figure. 



Fig. 13. A longitudinal section of several air-chambers, showing the concavity of the septa and the elements 

 of the siphuncle. The section does not pass tlirough the axis of the siphuncle, and does not show 

 the passage of the tube through the septa. Uamilton group. Hainhwgh, Erie county, N. T. 



