=). 
EMYDID. 359 
The total length of the plastron (hg. 456) 1s 272 mm.;_ but along the midline, from the 
front of the plastron to the bottom of the posterior notch, the length is about 265 mm. The 
anterior lobe has a length of about 85 mm. and a width of 140 mm. At the suture between the 
epiplastrals and the hyoplastra the width is 122 mm., and this width is continued backward 
about 22 mm. further. The entoplastron is 51 mm. wide. The anterior lip projects somewhat 
and has a width of 60 mm. 
The posterior lobe has a width of 134 mm. and a total length of go mm. Toward the hindei 
extremity the lobe narrows rather rapidly and is posteriorly deeply notcht. The humero- 
pectoral sulcus passes behind the entoplastron. The gulars extend along the midline for 
456. 
Fics. 455 AND 456.—Graptemys inornata. Carapace and plastron of type. about }. 
455. Carapace. 456. Plastron. 
47 mm.; the humerals, 2g mm.; the pectorals, 30 mm.; the abdominals, 63 mm.; the femorals, 
53 mm.; the anals, 3o mm. The bridges have a width of 100 mm. 
The present species is here vefeered with doubt to the genus Graptemys Agassiz. It can 
hardly belong to the genus Chrysemys as that is here defined and the type of w hich is C. picta. 
The shell of this White River species has some resemblance to that of Graptemys geo ogra phic a, 
having a low rounded dorsal carina and an elongated first suprapygal, like the living species 
just aeeaed. The species may belong to either Pseudemys or Trachemys; but it will be neces- 
sary to have the skull in order to detenmiie; its relationships with certainty. 
Genus TERRAPENE Merrem. 
Shell usually short and broad, rarely elongated. Neural bones hexagonal, with the broader 
end forward. The eighth neural usually absent. Plastron as broad as the opening of the 
carapace, composed of two distinct portions moyable on each other and the carapace, there 
being a ligamentous hinge between the hyoplastra and the hypoplastra and another on each 
side between the bones mentioned and the carapace. Zygomatic arch complete, deficient, 01 
wanting. Alveolar surfaces of the jaws narrow and without ridges. Choanz between fronts 
of orbits. Digits with little or no web. Tail short. 
Type: Perraipe ne carolina (Linn). 
The known members of this genus are confined to North America. The species are 
closely related, and their number is not certainly determined. On the number of the digits 
of the hinder feet and the condition of the zygomatic arch the genus has been, especially by 
