58 EMYSTROOSTII. 



Habits. I am not aware that the E. Troostii differs in its habits from the other 

 animals of its tribe. 



General Remarks. It is remarkable that the animal from which the accom- 

 panying figure was taken had six vertebral plates, and that apparently not the 

 result of injury. Another specimen possessed the usual number, and the shell 

 was broader in proportion. 



