EMYDID-fli. 



349 



Vertebral 



scute. 



Length Width. 



height of the eleventh is 29 mm.; its width along the free border, 22 mm. The pygal has a 

 height (antero-posterior dimension) of 23 mm. and a width of 21 mm. It has a deep median 

 notch; and there is a similar notch on each side of it. The interperipheral notches are not 



deep, and there are no notches where the sulci cross the borders 

 of the peripherals. In the latter respect this species differs from 

 T . elegans. 



The bones of the carapace are thin, the border of the median 

 costals being but little more than 2 mm. thick. 



The sulci are rather deeply imprest on the carapace. The form 

 and dimensions of the various scutes may be readily determined 

 from fig. 451. The table herewith gives the dimensions of the 

 vertebrals. 



The arrangement and forms of the scutes closely resemble 

 those of the specimen of T . rugosa already mentioned. 



The sulci separating the costal from the marginal scutes are arranged somewhat differently 

 in this species from the arrangement in T. rugosa and T. scripta. In T . rugosa the costo-mar- 



Figs. 451 and 452. Trachemys hilli. Carapace and plastron of type. X i- 

 451. Carapace. Front restored. 452. Plastron. Anterior lobe partly restored. 



irinal sulci run along on the peripherals at a considerable distance below the costo-peripheral 

 sutures from the nuchal to the eleventh peripheral. Here the sulcus rises somewhat and 

 crosses the midline on the hinder border of the suprapvgal. In T. scripta the arrangement is 

 the same to the eleventh peripheral, where it remains low down and crosses the upper third 

 of the pygal. In T. hilli from the front of the bridge the sulci appear to coincide closely with 

 the sutures until the seventh peripheral is reacht. Here the sulci descend on the peripherals, 

 but not far, and they cross the midline on'the upper part of the pygal. 



In the case of the neurals preserved there are some longitudinal wrinkles on the hinder 

 ends of the third and the fifth, just behind the sulci crossing these bones. On the costals is a 



