PLATE XXXV A. 



Orthoceras Pelops. 



Paue 233. 

 See Plates 35, 37, 78 B. 



Fig. 1. A large, imperfect individual, retaining its normal foi'm and convexity. Several additional cham 

 bers, belonging to the specimen, at the smaller extremity, are not represented iu tlie figure. 

 ClarkmiUe, N. Y. 



Fig. 2. Longitudinal section showing the depth of the chambera, taken from the middle of sxiecimen fig. 1. 



Fig. 3. A septum of specimen fig. 1, showing the position of the siphuncle. 



Fig. A. Longitudinal section showing traces of the siphuncle in its passage through the chambers. 



Fig. 6. A very large, flattened chamber of habitation belonging to this species, showing a constriction near 

 the a|>erture. Knox, N. T. 



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 Tantalus. 



I'age m. 

 See Plate 35. 



Fig. 7. Longitudinal section showing the depth of the chambei-a and the convexity of the septa." Traces of 



an expanded siphuncle shown iu 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 238. 

 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 fii-st 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. 



