PLATES AND EXPLANATIONS 
OF 
CEPHALOPODA. 
PLATE XXXV. 
Orthoceras Pelops. 
Page 233. 
See Plates 35 A, 37, 78 B. 
Fig-. 1. A fragment, preserving a considerable portion of the chamber of habitation, showing a gentle con¬ 
striction below the aperture. The great convexity of the septum at the lower extremity of the 
figure is due to the flattening of the specimen. Schoharie, N. Y. 
Figs. 2, 2 a. A septate fragment, retaining its form and septa, without compression; 2, a section showing 
size and position of siphuncle. Helderberg mountains. 
Fig. 3. Enlargement of a portion of the test from specimen fig. 2. 
Orthoceras luxum. 
Page 244. 
r See Plates 76, 77, 78, 78 B, 81, 112. 
Fig. 4. A crushed fragment, showing a usual exsolute condition of the air-chambers. Schoharie, N. Y. 
Fig. 5. A fragment of the septate portion of an individual, presenting the characters of the organic deposit 
on each side of the carina, and on the ventral walls of the chambers. 
Fig. 6. Same as the preceding, showing this feature in a less marked degree. 
Fig. 7. A small fragment, retaining, in the cast, evidences of the lamellose-striate surface of the test. 
Orthoceras Tantalus. 
Page 241. 
See Plate 35 A. 
Fig. 8. A specimen retaining a portion of the chamber of habitation and fifteen air-chambers. The banded 
or zoned appearance, so prominent in 0. cingulum, is here much less marked. 
Fig. 9. A septum of the preceding specimen, showing the size and position of the siphuncle, and the organic 
deposit on the septum around the siphuncle. 
Fig. 10. Portion of a large individual, presenting the same features as specimen figs. 8, 9. , 
Orthoceras carnosum. 
Page 258. 
Fig. 11. Ventral view of a specimen retaining the grand chamber and ten of the air-chambers, showing the 
surface characters and the sinus of the ornaments. Schoharie, N. Y. 
