EMYDIDZ. 309 
humeral sulci run directly backward. The bone is thickened backward a distance of 20 mm. 
The horn-covered band is 17 mm. wide at the hyoepiplastral suture. 
In 1870, as cited above, Dr. Leidy described his Emys jeanesi from a quite complete shell 
found near Fort Bridger. In 1873 he referred this specimen to his earlier LE. wyomingensis. 
An examination shows that its epiplastron is as nearly like that forming the type of E.w yoming- 
ensis as could be expected in two individuals of the same species. The width of that of E. 
jeanest is 54 mm.; the thickness at the midline, 11 mm.; behind the lateral teeth, 12 mm. As 
in the type of EF. wyomingensts, there is, on the upper surface, a broad longitudinal ridge 
flankt by broad grooves. The thickening of the upper surface extends backward about 20 mm. 
The width of the smooth band, at the hy oepiplastral suture, is 13 mm. There appears to be 
neither reason nor profit in regarding E. yeanesi as distinct specifically from £. wyomingensts. 
The type of E. yeanes: was figured by Leidy. Diagrammatic figures are here presented 
of both carapace (fig. 392) and plastron (fig. 393). 
An examination of the interior of the shell of this type shows that the inguinal buttresses 
were not so strongly developt as in most other species of Echmatemys. They arise from the 
FIGs. 392 AND 393.—Echmatemys wyomingensis. Carapace and plastron of type of 
Emys jeanest. XX}. U.S.N.M. 
392. Carapace. 393. Plastron. 
floor of the plastron at a line two-fifths the distance from the free border of the hinder lobe to 
the midline. The distances are respectively 29 mm. and 69 mm. The width of the smooth 
band, on the upper surface, at the hypoxiphiplastral suture, is 12 mm. The greatest thickness 
of the bone here is 13 mm. The axillary scute is mostly missing, but it appears to have 
extended backward only to the middle of the fourth marginal. The inguinal scute too is 
short, reaching forward only to the middle of the seventh marginal. 
No. 5988 of the American Museum furnishes the plastron complete and the carapace 
lacking peripherals 3 to 6 inclusive, of the right side, the distal ends of the 4 posterior costals 
of the same side, and the pygal. The specimen was obtained in 1903, on Little Dry Creek, 
Wyoming, and belongs to horizon B. The shell has been crusht downward after burial and 
the width considerably exaggerated. Both eleventh peripherals are present, but they stand 
apart about go mm., whereas in life they were separated only by a pygal about 20 mm. wide. 
The surface of the shell was smooth. There is no suggestion of a median keel. The length 
of the carapace (text-fg. 394) was close to 335 mm. The width may be regarded as having 
