Z PROCEEDINGS OF THE NATIONAL MUSEUM vol. 77 



Pseudemys. For the present, however, I shall follow Hay, who recog- 

 nizes no less than nine extinct species all referred to Trachemys. Five 

 of these, T. euglypha (Leidy), T. sculpta Hay, T. jarmani Hay, T. 

 nuchocarinata Hay, and T. delicata Hay were founded upon specimens 

 from Florida. All except T. delicata a supposed Pliocene species 

 are from the Pleistocene. T. bisornata originally described from 

 the Pleistocene of Texas has also been recognized ^ among Florida 

 materials. 



While there is reason to question the validity of some of these 

 species, as most of them were founded on fragmentary specimens, more 

 abundant and better preserved materials are necessary before a 

 revision can be attempted. 



Specimen (Cat. No. 11839, U. S. N. M.) here identified as 

 Trachemys sculpta Hay is a nearly complete uncrushed shell, lacking 

 the third and eleventh peripherals from the left side, and the eighth 

 and tenth from the right side; neural seven and eight, and the pygal. 

 The plastron lacks the epi-ento-and xiphiplastra. 



The carapace is strongly arched in all directiq^ns. Viewed from 

 above it is subovate in outline, broad in front, obtusely pointed 

 behind. The median anterior border shallowly concave. In a 

 straight line its greatest length is about 280 mm., the greatest trans- 

 verse diameter at mid length being about 230 mm. In elevation this 

 specimen is relatively greater than any of the living species of Pseu- 

 demys in the National collections; its maximum height being 137 mm. 

 Along the center of the carapace, within the areas of the vertebral 

 scutes the surface is somewhat swollen above the general contour of 

 the shell, culminating within vertebrals three and four in obtusely 

 rounded keels that are interrupted by the vertebral sulci separating 

 these dorsal scutes. The margin of the carapace behind the inguinal 

 notches is thin and comes to an acute edge that is shallowly scalloped. 

 The anterior margins are obtusely rounded except at the center which 

 is also acute. The sulci are everywhere deeply impressed. 



The entire dorsal surface is beautifully and ornately sculptured 

 with grooves, ridges and low pustular elevations. The areas within 

 the vertebral scutes are smoothest, but here too some sculpture is 

 present in the form of faint ridges and grooves that in general radiate 

 from the central region of each scute. On the costal bones traversed 

 by the intercostal sulci the sculpturing is much less pronounced than 

 on the others. The costals are traversed by grooves and ridges that 

 generally run parallel with the length of the animal. Many of the 

 ridges are broken up at varying intervals, thus forming elevations of 

 various sizes. The areas bordering the costo-peripheral sutut'e is 

 crossed at right angles by regular ridging, that forms a band extending 



3 Eighth Ann. Kept. Geol. Surv. of Florida, 1916, p. 67. 



