346 



FOSSIL TURTLES OF NORTH AMERICA. 



FIG. 449. Chrysemys timida. 

 Carapace. Xi. 



considerably deprest, but probably less so than its present height, 40 mm., indicates. We 

 can not determine to what extent, if any, the hinder border of the carapace was notcht. The 

 hinder peripherals are slightly recurved. Their free margins are acute. No carina is pres- 

 ent, but on the nuchal and the first neural there is a perceptible 

 elevation. In the region of the hinder neurals there is a decided 

 longitudinal depression. The surface is smooth, except that on 

 the outer ends of the costals there are longitudinal ridges and 

 grooves, due to the growth of the epidermal scutes. 



The neural bones are rather narrow in comparison with those 

 of C. ptcta. Most of them are hexagonal, with the broader end 

 forward. The dimensions of the neurals are shown in the table 

 on page 345. 



The nuchal had a median length of more than 30 mm., a mar- 

 ginal width of about 20 mm., and an extreme width of 35 mm. 

 The suprapygal plates are three in number. The first has a length 

 of 5.5 mm. and a width of 10 mm. The second is bifurcate, 

 like the same bone in Testudo, the hinder border being deeply 

 concave. The median length is 7 mm., the extreme width, 21 mm. 

 The third is nearly diamond-shaped, fitting in between the second 

 suprapygal and the pygal. It is 8 mm. long and 15 mm. wide. 

 The pygal is 22 mm. wide, 17 mm. long and 4.5 mm. thick. 



The first peripheral is 20 mm. fore and aft and the same 

 along the free margin. The eleventh is 18 mm. high and 17 mm. 

 along the free margin. 



The plastron is somewhat damaged. It is 157 mm. long. 

 The anterior lobe is 43 mm. long and 72 mm. wide at the base. 

 The lip is truncated and appears to have been 40 mm. wide. 



The hinder lobe is 55 mm. long and 84 mm. wide at the base. A broad notch occupied the 

 hinder end. The inguinal buttress is attacht to the fifth costal plate. 



The entoplastron is 25 mm. long and 27 mm. wide. The hypoxiphiplastral suture appears 

 to have run nearly straight across the hinder plastral lobe. 



The hyoplastrals occupy about 36 mm. of the midhne; the hypoplastrals, about 48 mm.; 

 the xiphiplastrals, about 37 mm. 



The vertebral scutes are rather broad and are strongly bracket-shaped laterally. Their 

 dimensions are given in tabular form on the preceding page. 



The inferior surface of the plastron is injured so that few of the sulci can be traced. The 

 abdomino-femoral passes between the inguinal notches with a slight convexity forward. The 

 femoro-anal sulcus is directed outward and backward. The femoral scutes are about 18 mm. 

 long on the midline; the anals, about 30 mm. 



Genus DEIROCHELYS Agassiz. 



Differs from Chrysemys in having the heads of the ribs long and thread-like, and the shell 

 sculptured. 



Type: Deirochelys reticulata (Daudin). 



The following species is referred provisionally to Deirochelys. 



Deirochelys floridana sp. nov. 

 Plate 54, figs. I, 2; text-fig. 450. 



The nuchal bone on which the present species is based is a part of the Jarman collection, 

 the property of the Vanderbilt University, Nashville, Tennessee. The collection was obtained 

 in Hillsboro County, Florida, and the deposits probably belong to the Peace Creek beds. 

 While the generic position of the species is not assured, the form of the bone and especially its 

 sculpture so much resemble that of Deirochelys reticulata that it is referred to the latter inter- 

 esting genus. 



