PLATE ICY, 
Cyrtoceras liratum. 
Page 364. 
Fig-. 1. Lateral view of the specimen, showing the curvature of the tube, the septate apical portion, and the 
. regular, longitudinal furrows ornamenting the shell. Goniatite limestone. Marcellus, N. Y. 
GOMPHOCERAS TUMIPUM. 
Page 351. 
See Plate 93. 
Fig. 2. The apical portion of an individual, showing the depth of the air-chambers and the enlargement of 
the tube. Chemung group. Ithaca, N. Y. 
Fig. 3. An imperfect fragment, which has been much disturbed by compression, doubtfully referred to 
this species, but occurring in the same association with the preceding. Chemung group. 
Ithaca, N. Y. 
Fig. 4. A compressed individual, showing the branches of a parasitic Bryozoan on the surface of the tube. 
Chemung group. Cascadilla Creek, Ithaca, N. Y. 
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. Y. 
Fig. 7. A specimen much compressed, but showing the attenuate apex and subglobose chamber of habita¬ 
tion. Several branches of two species of parasitic Bryozoans are attached to the grand 
, chamber. Chemung group. Ithaca, N. Y. 
Gomphoceras pingue. 
Page 346. 
See Plate 94. 
Fig. 6. The apical portion of an individual which has been disturbed by compression, but referred to this 
species on account of its association and the depth of the air-chambers. Hamilton group. 
North of Cazenovia, N. Y. 
Cyrtoceras (Gomphoceras) formosum. 
Page 362. 
Fig. 8. The chamber of habitation, showing the surface ornaments of the tube, which become in part obso¬ 
lete near the aperture. The lines in the fig-ure, crossing the hiatus in the margin of the aper¬ 
ture, do not appear in the specimen. Hamilton group. Dresden, N. Y. 
Fig. 9. An enlargement of the surface, showing more minutely the charactex-s of the ornamentation. 
Gomphoceras lunatum. 
Page 341. 
Fig. 10. The chamber of habitation, with several attached air-chambei-s. 
Fig. 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 Ig. 10, showing the enlai-gement of the 
tube and the variation in the depth of the air-chambers. Portions of the test, showing the 
ox-namentation of the sui-face, the ci-enulations and venti*al furrow, ai-e not l-epi-esented in 
the figui-e. 
Fig. 13. A longitudinal section of several air-chambei-s, showing the concavity of the septa and the elements 
of the siphuncle. The.section does not pass through the axis of the siphuncle, and does not show 
the passage of the tube through the septa. Hamilton groxxp. Hamburgh, JEh'ie county, N. Y. 
