132 MEMOIRS OF THE CARNEGIE MUSEUM 



femoral sulcus, and from this point posteriorly the lateral borders converge quite 

 rapidly to the posterior end, which is deeply notched. The great breadth of the 

 lobes in E. douglassi leaves but little space for the exit of the limbs, and in front the 

 exit is still further closed by the upward curve of the anterior lobe as in E. callopyge 

 Hay. Transversely the plastron is angularly concave, but how much of this de- 

 pression may be attributed to postmortem causes it is impossible to determine. It 

 may be largely sexual, and in that case this specimen would represent a male. 



The entoplastron is pear-shaped and extends forward to within 11 mm. of 

 the anterior margin of the lobe, a most unusual position in the Emj^didae. The 

 length of the entoplastron is 79 mm.; its width 71 mm. The bridge has a width of 

 167 mm. In this specimen, as shown in Fig. 12, there are intergular scutes, which 

 overlap the entoplastron. On the left side the gular-humeral sulcus follows the 

 usual course, reaching the margin of the lobe immediately posterior to the toothed 

 projection marking the external boundary of the lip. On the right side, however, 

 there is no trace of this sulcus. Intergulars are not known in any other member of 

 the Emydidae, and it may be that the scutes here designated as intergulars are the 

 gulars, and that the extra scute on the left side is supernumerary. Even should 

 that be the case, the position of the sulcus crossing the border on the mesiad side 

 of the toothed projection is unusual, and probably constitutes an individual vari- 

 ation, the true condition of which can only be cleared up by the discovery of ad- 

 ditional specimens pertaining to this species. 



The pectorals do not reach the entop'astron, but at the center pass 6 mm. 

 behind it. They have their greatest width of 60 mm. at the center. The humerals 

 meet along the midline for a distance of 65 mm. ; the abdominals for 98 mm. ; the 

 femorals for 68 mm. ; and the anals for 55 mm. 



The hyoplastrals are 85 mm. wide antero-posteriorly at the midline, the left 

 being slightly more. Each extends laterally about 132 mm. The hypoplastrals 

 meet on the midline for a distance of 122 mm.; the xiphiplastrals for a distance of 

 83 mm. The notch between their hinder ends is 20 mm. deep, with a greatest 

 width of 50 mm. 



In the general shape and contour of the shell this species closely resembles 

 Echmatemys stevensoniana (Leidy), from the Bridger beds of Wyoming. It differs 

 from that species, however, in the deep emargination of the anterior lobe and the 

 failure of the pectoral scutes to reach the entoplastron. 



Echmatemys douglassi is distinguished from all described species of the genus 

 by the deep emargination of the anterior median border of the anterior lobe; by the 

 short and wide anterior lobe, the length of which at the center is only fifty per cent. 



