PLATE LXXXII. 
Orthoceras crotalum. 
Page 296. 
See Plates 42, 113. 
Fig. 1. An imperfect specimen, showing the characters of the tube at the aperture, and the surface-mark¬ 
ings of the shell. Pratt's Falls, Onondaga county, N. Y. 
Fig. 2. A fragment with the annulations somewhat irregular in frequency. The tube has a slight curva¬ 
ture, either natural or from compression. Delphi, N. Y. 
Fig. 3. A small, slightly compressed specimen, showing the surface ornaments, and the increase in the 
prominence of the annulations toward the larger extremity. Fast shore of Cayuga Lake, N. Y. 
Fig. 4. A lateral view of the same, showing a curvature of the tube near the apex. 
Fig. 5. The initial extremity, showing the incipient annulations of the apex. East shore of Cayuga Lake . N. Y. 
Fig. 6. The apical portion of an individual, showing more satisfactorily the increase in the prominence, of 
the annulations, and the gradual change in their frequency toward the chamber of habitation. 
East Shore of Cayuga Lake, N. F. 
Orthoceras iEoEA. 
Page 295. 
Fig. 7. A fragment of the chambered portion, showing the annulations and surface-markings of the shell. 
Fig. 8. A septum of the preceding, showing the central position of the siphuncle. 
Fig. 9. A fragment of the internal mould. The furrows in this example are nearly the reverse of the 
exterior surface, as shown on other specimens. Pratt's Falls, Onondaga county, N. Y. 
Fig. 10. A small fragment preserving the surface ornamentation. Greneseo, Livingston county, N. Y. 
Fig. 11. A portion, apparently, of the chamber of habitation, showing the low, transverse undulations, and 
the strong longitudinal ridges with smaller intermediate ridges and striae. Greneseo, Livingston 
county, N. Y. 
Fig. 12. A fragment of a large individual, similar to the preceding, showing the low undulations of the 
tube. In the calcareous beds of the Hamilton group in Madison county, N. Y. 
Fig. 13. A septum of the same, showing the position of the siphuncle. 
Orthoceras nuntittm. 
Page 299. 
Figs. 14, 15. Longitudinal sections of specimens firmly imbedded in the surrounding rock, and not furnishing 
sufficient data for positive determination. The specimens are referred to this species on 
account of their association.. Pratt's Falls, Onondaga county, N. Y. 
Orthoceras caelamen. 
Page 298. 
See Plates 42, 43, 113. 
Fig. 16. A portion of the test enlarged, from specimen fig. 10, pi. 42, showing the characteristic rounded, 
interrupted, longitudinal striae, crossed by finjer striae and broad, lamellose lines of growth. 
Ontario county, N. Y. 
Orthoceras CEdiptjs. 
Page 294. 
See Plate 37. 
Fig. 17. A crushed fragment of the chamber of habitation and several attached air-chambers, preserving 
. portions of the test, and showing on the internal mould the strong longitudinal ridges. Gfeneseo, 
Livingston county, N. Y. 
Orthoceras Thestor. 
Page 302. 
Fig. 18. A fragment, with the upper portion of the tube flattened from compression, and partially covered 
with the adhering shell. The figure shows the very numerous, regular annulations of the tube. 
Marcellus shale. Schoharie, N. Y. 
