PLATE XXIV A. 
Orthoceras Pelops. 
Page 233. 
See Plates 35, 37, 78 B. 
Fig. 1. A large, imperfect individual, retaining its normal form and convexity. Several additional cham 
bers, belonging to the specimen, at the smaller extremity, are not represented in the figure. 
Clarksville, N. T. 
Fig. 2. Longitudinal section showing _the depth of the chambers, taken from the middle of specimen fig. 1. 
Fig. 3. A septum of specimen fig. 1, showing the position of the siphuncle. 
Fig. 4. Longitudinal section showing traces of the siphuncle in its passage through the chambers. 
Fig. 5. A very large, flattened chamber of habitation belonging to this species, showing a constriction near 
the aperture. Knox, N. Y. 
Fig. 6. Longitudinal section showing the depth of the chambers somewhat shallower than usual, the con¬ 
cavity of the septa, and remains of the siphuncle. 
Orthoceras Tantalos. 
Page 241. 
See Plate 35. 
Fig. 7. Longitudinal section showing the depth of the chambers and the convexity of the septa." Traces of 
an expanded siphuncle shown in the specimen are not represented 
Fig. 10. A septum showing the size and position of the siphuncle, surrounded by an areola, and an organic 
deposit on the septum. 
Orthoceras Ohioense. 
Page 236. 
See Plate 36. 
Fig. 8. Longitudinal section from specimen (plate 36, fig. 4). The septa are mostly broken away. Evi¬ 
dences of a slightly expanded siphuncle are shown in the first two chambers, but not repre¬ 
sented in the figure. Delaware, Ohio. 
Fig. 9. A septum of preceding specimen, showing size and position of the siphuncle. 
