262 0. P. Hay — Fossil Turtles in the Marsh Collection. 



Dimensions. Baena marshi. Baena hatcheri. 



Length of plastron 260 ± 305 



Width of bridge 120 115 



Length of anterior lobe 70 106 



Width of anterior lobe 95 115 



Length of posterior lobe 65 ± 98 



Width of posterior lobe 90 120 



Figure 1. — Baena marshi. Diagram of plastron. 



It will be observed that, while the plastron of B. hatcheri 

 is considerably longer, the bridge is slightly shorter. Further, 

 the lengths of the anterior and posterior lobes of B. marshi 

 are much less in proportion to the total length of the plastron 

 than they are in B. hatcheri. 



The central region of the plastron is concave. This may 

 indicate that the individual was a male. The mesoplastra are 

 large, wedge-shaped bones. They meet along the midline for 

 a distance of 23 mm , and their outer ends are 65 mm wide. 



The following are the antero-posterior widths of the various 

 plastral scutes : Intergulars, 17 mm ; gulars, 10 mm ; numerals, 

 46 mm ; pectorals, 50 mra ; abdominals, 47 mm ; femorals, 53 mm ; anals, 

 about 45 mm . On the bridges the*re are four inframarginals, of 

 which the inguinal is the largest, and the axillary somewhat 

 the smallest. 



