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. 
1c. A transverse section of the specimen, at the upper extremity of 1 a, showing the excentric position of the 
siphuncle. 
1d,e. A fragment of another specimen, showing the same distance of the septa and excentric position of the 
siphuncle. 
if. 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 a, 8. 279. 11. ENpocERAs ARCTIVENTRUM. (Pag. 217.) 
Fig. 3. 280. 12. ENpocERAS ANGUSTICAMERATUM. (Pag. 218.) 
