186 FOSSIL TURTLES OF NORTH AMERICA. 
deposits, near Fairbury, Nebraska. An extended description of the species, with figures, is 
given by Williston, as cited above. A number of his drawings have been reproduced in the 
present work. 
This turtle was evidently a large one. The skull (figs. 238, 239) is uncrusht, but the hinder 
portion of the base is damaged. The total length from the snout to the end of the supraoc- 
cipital spine is 205 mm.; the width thru the quadrates is 145 mm. The skull is remarkable 
for the length of the posterior lateral, or squamosal, processes. These lack but little of extend- 
ing backward as far as the supraoccipital process; while the latter has about its usual length. 
The parietals are unusually narrow. Williston informs us that these bones join the squamosals. 
The frontals and the prefrontals together occupy the area occupied in Chelonia mydas by the 
frontals. In front of the prefrontals come the large nasals, bones rarely found in Cryptodira. 
These nasals are about 13 mm. long and each is about 1g mm. wide. The antero-posterior 
Fics. 240-243.—Desmatochelys lowt. Portions of the type. 
240. Humerus. 242. Fragments of peripheral bones. 
241. Pelvic bones. #/, illum; isch, ischiuin; pub, pubis. 243. Fragments of plastron and peripheral bones. 
diameter of the nasal opening is 24 mm.; the transverse diameter, 18 mm. It looks strongly 
upward. The orbits have an antero-posterior diameter of 60 mm. The interorbital space is 
58 mm. wide. 
The palate (fig. 239) is remarkable on several accounts. The choane are considerably 
further forward than they are in the Cheloniide; but what is more important, there is no Hoor 
beneath them formed by the bones bounding them. Each is at the anterior end of a longitudinal 
concavity, whose depth diminishes backward. The transverse sutures between the palatines 
and the pterygoids are relatively much further backward than they are in Chelonia mydas. 
The pterygoid processes are therefore more posterior than usual. The possession of posterior 
palatine foramina is another feature distinguishing this species from any of the modern sea- 
turtles. They are small, and may be regarded as vestigial. Behind the pterygoid processes 
the palate narrows to a width of about 22 mm. In front of the processes named there 1s another 
slight constriction of the palate. The longitudinal median sutures are not discernible, and it 
is not certain that the palatines joined in the midline. 
