18 F. B. Loomis — Turtles from the Upper Harrison Beds. 



of the Amherst Collection) which includes the portion found 

 by the Carnegie party, together with the front of the plastron, 

 the skull, shoulder girdle, humerus, pelvis, femur, a large 

 number of dermal ossicles and fragments of other bones. 



Three species of giant land tortoises have been described, 

 all agreeing in a general way and being distinguished by hav- 

 ing a dermal armature of small bones, in addition to the shell. 

 These are Testudo osborniana from the Pawnee Creek beds, 

 T. impensa from the Loup Fork of Montana, and T. orthopygia 

 from the Upper Miocene of Kansas. To this group T. areni- 

 vaga belongs, making four representatives from the middle 

 West. 



The skull of T arenivaga is relatively the widest of any of the 

 known forms in this group (and all of the four are known by 

 practically the whole skeleton), triangular in form, with rather 



Fig. 1. 



Fig. 1. Testudo arenivaga, the skull from the palatal aspect. % 

 nat. size. 



Fig. la. Lower jaw from the side. % nat. size. 



heavy bones, and with the lateral angles extending slightly 

 behind the occipital condyle. It is also relatively low. 



Measurements. 



Length, snout to occipital condyle 1 I4 mm 



Width across the quadrates .__ 84 mm 



Height at back of maxilla Sl max 



The top of the frontal is somewhat crushed, but the margins 

 remain'and show the interorbital region to be moderately wide 



