4 PROCEEDINGS OF THE NATIONAL MUSEUM vol.82 



The entoplastron is 46 mm (37 mm) long and 53 mm (45 mm) wide. 

 It is crossed posteriorly by the humero-pectoral sulcus. 



The posterior lobe has a greatest width of 134 mm (129 mm) and 

 a length of 100 mm (100 mm). Toward the posterior extremity the 

 lobe narrows rapidly, terminating in a deeply notched end. The edges 

 of the posterior lobe are everywhere sharply edged. 



Table 1. — Dimensions of neurals of Pseudemys idahoensis 



The bridge is 115 mm (95 mm) wide. The gulars extend along the 

 midline for 43 mm (40 mm) and strongly overlap the entoplastron. 

 The humerals meet on the midline for 27 mm (23 mm), the pectorals 

 46 mm (39 mm), the abdominals 66 mm (66 mm), the femorals 40 

 mm (34 mm), and the anals 56 mm (50 mm). 



A third specimen, U.S.N.M. No. 12232, consisting of the posterior 

 lobe of the plastron, was collected from this same fossil deposit by 

 N. H. Boss in 1931. Except for its smaller size it is in perfect accord 

 with the type specimens. 



Table 2. — Dimensions of vertebral scutes of Pseudemys idahoensis 



