290 FOSSIL TURTLES OF NORTH AMERICA. 



cated. The anterior lobe is 240 mm. wide at the base and 118 mm. long. There is no 

 specialized epiplastral lip. The bones are about 10 mm. thick, and the free borders are sub- 

 acute. The posterior lobe is 144 mm. long and 205 mm. wide at the base. The lateral borders 

 are somewhat convex in outline, and they converge toward the rear. The latter is truncated 

 and about 50 mm. wide. The median and the hinder portions of the lobe are thin, from 4 mm. 

 to 8 mm. From the acute borders of the hypoplastron the bone thickens inward a distance of 

 30 mm., then grows thinner. 



The axillary and the inguinal buttresses extend inward little further than the free borders 

 of their respective lobes. The entoplastron is diamond-shaped, with the posterior angle 

 rounded. It is 75 mm. wide and 65 mm. long. The hyoplastra occupy 1 12 mm. of the midline; 

 the hypoplastra about no mm.; the xiphiplastra, 100 mm. A very careful examination fails 

 to discover the presence of mesoplastra. 



The gular scutes appear extraordinarily large and the shallow grooves which are taken to 

 represent them may be deceptive. No evidences are found of the presence of intergulars, 

 but they may have existed. The gulars overlap the front of the entoplastron. The humero- 

 pectoral sulcus does not cross any part of the entoplastron. The humerals extend along the 

 midline 38 mm.; the pectorals, 75 mm.; the abdominals, 62 mm.; the femorals, no mm.; 

 the anals, 40 mm. It is impossible to make any statement regarding the scutes of the bridges. 



Genus CLEMMYS Ritgen. 



Shell only moderately elevated. Neural plates hexagonal, with the broader ends forward. 

 Usually, but not always, at least some traces of a dorsal keel. Axillary and inguinal buttresses 

 feeble, extending upward little, if any, above the lower borders of the costals; the inguinal 

 articulating with the fifth costal. Humero-pectoral sulcus crossing the entoplastron. Plastron 

 notcht behind. Triturating surfaces of the jaws narrow, not furnisht with ridges. Choanae 

 between the eyes. 



Type: Clemmys punctata Schoepff=C. guttata Schneider. 



At the present day there are about 6 living species of this genus. These inhabit Europe, 

 northwest Africa, southwestern Asia, China, Japan, and North America. Four of the known 

 species occupy portions of North America, 3 of them being limited to the region east of the 

 Mississippi River, I to the Pacific coast. In the present work five fossil species, all based 

 unfortunately on fragmentary materials, are referred to this genus. One of these, C. saxea, 

 belongs to beds believed to be Pliocene, a second species, C. hesperia, to the Mascall beds of 

 the Upper Miocene; a third species, C. morrisics, to the Bridger Eocene; a fourth supposed 

 species is C. percrassa Cope from the Pleistocene cave near Port Kennedy, Pennsylvania. 

 It seems probable that North America is the original home of the genus and that the Old 

 World has received its stock from the New World. 



The descriptions of the species of this genus are introduced at this stage because it appears 

 to the writer that the structure is rather primitive and that from this genus may have been 

 developt almost any of the other forms of the Emydidae. 



1. Eocene species (Bridger beds): 



Resembling C. muhlenbergi mornsia 



2. Upper Miocene species (Mascall beds): 



Resembling C. marmorata hesperia 



3. Pliocene species (Rattlesnake beds): 



Pygal bone transversely convex saxea 



4. Pleistocene species: 



Hinder lobe greatly thickened percrassa 



Hinder lobe moderately thickened insculpta 



Clemmys morrisiae sp. nov. 

 Plate 45, figs. 1-3; text-figs. 359, 360. 



Of this interesting species there were collected by the American Museum expedition of 

 1903, in the western portion of Grizzly Buttes, portions of 4 individuals. These now have the 



