350 FOSSIL TURTLES OF NORTH AMERICA. 
Genus PSEUDEMYS Gray. 
Shell in general like that of Trachemys. Triturating surface of the upper jaw broad all 
round, with a strongly developt tuberculated median ridge. Lower jaw with broad surface 
and a median ridge; its lower surface flat. 
Type: Pseudemys rubriventris Leconte. 
. Pseudemys extincta sp. nov. 
Plate 54, fig. 13. 
‘The basis of the present species is a nuchal bone belonging to the Jarman collection, the 
property of Vanderbilt University. The collection was made in Hillsboro County, Florida, 
from beds belonging probably to the Peace Creek formation. 
This nuchal is referred to Pseude mys because of its resemblance to that of P. rubriventris, 
of the Southern States. The hinder border is somewhat water-worn, but it evidently follows 
closely the sutural edge. The median length is 62 mm.; the frontal width, 33 mm.; the 
maximum width, 70 mm. The anterior border is acute. From this the bone thickens back- 
ward about 30 mm., where is becomes 18 mm. at the midline, 15 mm. at the articulation with 
the first pepe Where the bone joins the first neural it is 5 mm. thick. The nuchal scute 
is 26 mm. long, 9 mm. wide in front, 19 mm. behind. The first vertebral is 48 mm. wide in 
front, contracting behind this, then again expanding. The first marginal has a length, fore and 
aft, of 37 mm. Its union with the first costal on this bone is only 10 mm. long. 
The upper surface of this bone is in general smooth, but there are traces of a sculpture, 
produced by the growth of the scutes. On the nuchal area the low ridges run parallel with the 
midline; so also do those on the area of the first vertebral. Those on the areas of the first 
marginals run outward and forward at an angle of about 45° with the midline. The ridges on 
the areas of the first costals run outward aad backward at a small angle with the aa alice’ 
With the other bones from the region about Tampa Bay there come many portions of 
plastrons, some of which probably belong to the present species. However, there is no way 
for connecting any plastral lip, for instance, with any nuchal bone. The writer describes, 
from that region, a number of species founded on nuchal bones, a quite characteristic part of 
the Meletond It remains for collectors and students to find and record other bones 1n their 
natural association with these various nuchals. 
Pseudemys czlata sp. nov. 
Plate 57, figs. 1-6; text-fig. 454. 
This name is based on some bones which belong to the U. S. National Museum. They 
were obtained from ‘‘Mason’s bone bed,” somewhere in Levy County, Florida, and are 
supposed, but not known, to belong to the Pleistocene epoch. They may belong to the Peace 
Creek formation. The bones bear the U. S. National Museum’s number 2 2508. They appear 
to be parts of at least 2 individuals, one considerably larger than the other. Of the larger 
individual there are present the nuchal; the distal end of the third costal, that of probably 
the left side; the left fifth costal; the proximal end of the seventh right costal; the third left 
peripheral; three posterior peripherals; the left epiplastron; and the left hypoplastron. 
Should it happen that more than one species is here included, the nuchal bone is to be regarded 
as the type. 
‘This species is conspicuous for its sculpture, which resembles that of Trachemys scripta, 
now living in the Southern States. 
The nuchal bone (plate 57, fig. 1) is 45 mm. long and 23 mm. wide in front, and 55 mm, 
wide where widest. The free border is acute; the greatest thickness, 10 mm. 
The third costal is 35 mm. wide distally and nearly 5 mm. thick at the sutural edge. The 
hfth costal (fig. 2) is 25 mm. wide and 7 mm. thick at the costo-vertebral sulcus, and 32 mm. 
wide at the distal end. The costo-vertebral sulcus crosses the proximal end at about lo mm. 
from the articulation with the neural. On the inner side of the distal half there is a prominent 
ridge. In the lower end of this ridge is an excavation for the inguinal buttress. This buttress 
rose about 20 mm. above the lower border of the costal. The seventh costal is 15 mm. wide 
