18 

 Sttlbmts nebhascensis, Leidy. 



This species has already been recorded by Cope, (this volume, pt. I, p. 6) from the head- 

 waters of Swift-current creek in Bone coulee (collection of 1884), who considered that certain 

 fragments from this locality were not distinguishable from Leidy's species from the Oligocene 

 of South Dakota and Colorado. The 1904 collection includes. parts of the shell of a tortoise 

 which is also, apparently, referable to the same species. 



Testudo exounata, Lambe, 

 Plate I, figs 20, 21 and 22. 

 Testudo exornata, Lambe, 1906. Ottawa Naturalist, vol. XIX, p. 187, pi. 3, figs. 1, 2 and 3. 



Among the chelonian remains of the Cypress Hills Oligocene collection of 1904 are parts 

 of a number of costal plates that were described in 1906, as appertaining to a new species 

 of Tesiudo, under the above name. 



The specimens were found separately, but were considered to belong, evidently, to the same 

 species. The three figured are the proximal end of the left first costal, the distal half of the 

 left fifth costal, and the proximal end of the left sixth costal. 



All the specimens show decided groove markings. The distal end of the fifth costal 

 plate, (figure 20, the type of the species), is particularly narrow and thick, but its outline indi- 

 cates that the bone when entire had a considerable breadth proximal ly. Its upper surface 

 presents a number of parallel shallow furrows in the direction of the length of the carapace. 

 It is thickened along its posterior articular border where it joined the similarly thickened 

 anterior border of the sixth costal, thus forming a stout ridge for the reception of the inguinal 

 buttress. 



The specimen shown in figure 21, is apparently the proximal end qf the left sixth costal 

 plate. This costal when complete was evidently much broader toward its outer end. Deep 

 sulci on the upper surface mark the position of the fourth vertebral, also the third, and fourth 

 costal shields. Distinct grooves also cross this plate from side to side near its inner end, where 

 the sutural surfaces for articulation with the sixth and seventh neural plates are preserved. 



The third specimen, figure 22, is the inner end of the left first costal. On its surface are 

 concentric grooves indicating an epidermal shield pattern such as is found in some of the 

 modern species of the genus. 



These specimens show that the costal plates were alternately narrow and broad distally, 

 and broad and narrow proximally : a common character of species of Testudo. 



Measurements. 



MM. 

 1st Costal plate. Plate I, figure "22 : — 



Maximum thickness at centre of proximal end 7 



Thickness of specimen at anterior suture 5 



" " " posterior " . 4 



5th Costal plate. Type. Plate I, figure 20 :— 



Thickness at proximal end of specimen 5 



" near distal end at anterior suture .... 5 



" distallj' near posterior suture .... 8 



6th Costal plate. Plate 1, figure 21 : — 



Thickness at proximal end g 



