PLATE 51. 
Fig. 1. 
270. 23. Orthoceras amplicameratum. 
(Pag. 205.) 
1 a, b. Parts of the same individual, preserving a large portion of the outer chamber, with an equal length of 
the septate part of the tube. 
1 c. A transverse section of the specimen, at the upper extremity of 1 a, showing the excentric position of the 
siphuncle. 
1 d, e. A fragment of another specimen, showing the same distance of the septa and excentric position of the 
siphuncle. 
1 /. A fragment of the septate portion of a much larger specimen. 
1 g, Transverse section of the same, showing the position of the siphuncle. 
Fig. 2 «, b. 
279. 11. Endoceras arctiventrum. 
(Pag. 217.) 
Fig. 3. 
280. 12. Endoceras angusticameratum. 
(Pag. 218.) 
