BMYDID.&. 



The first suprapygal has a length of 34 mm. and a width of 29 mm. The second supra- 

 pygal is 38 mm. long and about 78 mm. wide. 



The dimensions of the peripherals appear in the following table. 



The free border of the nuchal and that of the first pair of peripherals are acute. 



The vertebral scutes are long and narrow. The dimensions of these and the marginal 

 scutes are given in the tables above. 



As stated already, the plastron (fig. 408) has a length of 370 mm. The anterior lobe is 102 

 mm. long and 163 mm. wide. The length is therefore about 63 per cent, of the width. The 



407. 



FIGS. 407 AND 408. Echmatemys haydeni. Carapace and plastron. X }. No. 3943 A. M. N. H. 



407. Carapace. 



408. Plastron. 



free border is acute on the hyoplastrals, but becomes thickened and subacute and finally 

 rounded near the lip. The latter is 63 mm. wide. This has the appearance of having been cut 

 off square in front, with a short, blunt tooth on each side. On the upper side (fig. 409), from 

 the acute free border of the lip, the bone thickens backward a distance of 25 mm., where 

 the thickness is 14 mm. The width of the horn-covered surface at the union of the epiplastral 

 and hyoplastral bones is 22 mm. The entoplastron has a length of 66 mm. and a width of 75 

 mm. The bridge is 148 mm. wide. 



