144 ON A TORTOISE FOUND IN FLORIDA AND CUBA. 



found to be tolerably abundant in the brackish ponds, 

 where it seemed the only tortoise, during our own collect- 

 ing there. It is closely related to C. pennsylvanicum. 

 In the amount of differentiation, and its character, its case 

 bears much resemblance to that of Scaphiopus albus from 

 the same locality, and it is very likely there are other spe- 

 cies similarly modified by the same influences that have 

 caused the mentioned forms to differ so much from their 

 kindred of the mainland. In a study of the causes of va- 

 riation or of the origin of species such cases are of the great- 

 est importance. Whether the type originated on both 

 islands or was carried from one to the other may not be 

 determined from the present material. The form here de- 

 scribed is placed on record in literature under the name 

 of the eminent osteologist, Dr. George Baur of Clark Uni- 

 versity. 



