EMYDID&. 349 
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 
Vertebral 5 . 
Length Width. ie elegans. 
scute. 
: The bones of the carapace are thin, the border of the median 
as costals being but little more than 2 mm. thick. 
: = a The sulci are rather deeply imprest on the carapace. The form 
3 35 47 and dimensions of the various scutes may be readily determined 
F i is 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 7. 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- 
we iay t aa 
a, ra ‘ 
\ 
F | 
| 
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4 ee 
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451. 452. 
{ 
aes |} Y 
* f / 
eee ee eee 
Fics. 451 AND 452.—Trachemys hill. Carapace and plastron of type. 4. 
451. Carapace. Front restored. 452. Plastron. Anterior lobe partly restored. 
ginal 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 suprapygal. 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 
