TESTUDINATA. 



127 



costal has its posterior alar portion twice as wide as the rib portion ; its 

 suture with the first costal is very oblique, and is bounded behind by a rab- 

 bet-edge. The last costals are peculiar in their union throughout their entire 

 length without emargination for pygal, and in the gently convex posterior 

 outline (with projecting rib end), differing in these respects markedly from 

 P. multifoveatus and P. trionycJwides. 



Measurements. 



No. 1. Length of last costal common suture 045 



Length of last costal anterior suture 063 



Length of last costal exterior horder 052 



Width of middle costal 021 



Thickness of middle costal 004 



No. 2. Width of first costal, proximally 026 



Width of first costal behind rib, distally 014 



No. 3. Width of middle costal 021 



This handsomely marked turtle is quite peculiar in its sculpture, which 

 departs more from ordinary patterns than any of those referred to the 

 present genus. 



Two specimens from Cottonwood Creek, Wyoming. 



ANOSTIRA Leidy. 



Proceedings of Academy of Natural Sciences, 1871, p. 102. 



In this genus the epidennis was thin and adherent to the bones, and 

 not divided into scuta. The carapace is composed, as in Emydidce, of costal 

 vertebral, and marginal bones, the last united to the first by suture and 

 gomphosis. The series of vertebrals does not continue to the caudal except 

 by the intervention of a pygal. The sternum is cruciform, with narrow 

 longitudinal prolongations or lobes, and narrow bridges. It appears not to 

 have possessed any fontanelles, but the presence of mesosternum is not yet 

 fully made out. The cranium and limbs are unknown. 



This genus must be regarded as an interesting intermediate type con- 

 necting Plastomenus and Chelydra or Dermatemys. In skin and sculpture it 

 is identical with the first; in carapace and plastron most like Chelydra. 



Two species, a large and a small, are known. 



ilOM^ 



