624 GEOLOGICAL SURVEY OF THE TEERITORIES. 



M. 



Width of extremity posterior lobe , . 0r>7 



Leii^h of uucbal scuta 030 



Length of third marginal 0'J.?> 



Width of third marginal 020 



Width of fourth marginal 024 



Length of fourth marginal 028 



Length of eighth marginal 050 



Width of eighth marginal 035 



This species differs in many details from tlie i^receding species, nota- 

 bly in the form of the marginals. The anterior are wider than in either 

 species, while the median are narrow as in C. undatum. The sculpture 

 is very distinct from that of either. 



From the Bad Lands of Ham's Fork, Wyoming. 



Baena ponderosa. Cope, sp. nov. 



Established on numerous fragments of a specimen of a species which 

 I cannot refer to this genus with certainty, but which agrees with 

 the species already known in some particulars of structure. Thus the 

 last marginal plates were separated by an excavation of the posterior 

 border; at least this is the only position to which I can refer a portion 

 of the maj'gin of the carapace where the marginal scutes suddenly cease ; 

 the lateral ribs of the bridge are received into a deep pit between two 

 costals. 



The marginal and other bones are very massive, much more so than 

 in any other known water- tortoise of this formation. The margins of 

 the former are thickened, especially at the last marginal scute, which 

 is on a massive protuberance. The sutures are entirely regular. The 

 lateral marginal scuta are about as long as broad. The surface of the 

 shell is marked with irregular impressions, which are sometimes like 

 rain-drop i^its. A posterior vertebral bone possesses a median rib simi- 

 lar to that in Bermatemys vyomingensis. 



Measurements. 



M. 



Length of an anterior marginal scute 045 



Width of an anterior marginal scute 039 



Thickness of bone at anterior marginal scute 023 



Length of a free marginal bone 050 



Width of a free marginal bone 057 



Length of iirst marginal of bridge 060 



Thickness at simple end 023 



From the Bad Lands of Ham's Fork, Wyoming. 

 DEEMATEMYS, Gray. 



Baptemys, Leidy, loc. cit. 

 This genus is similar to Emys in the structure of the carapace and 

 plastron, except that the lobes of the latter are narrower and shorter. 

 The scuta are similar, excepting that there is a series of intermarginals 

 on the bridge on each side. There are thirteen marginals on each side, 

 those of the last pair in contact throughout. In a specimen of the only 

 species known, I find a trace of an intergular scute as is sometimes seen 

 in 1). berardii, now living in Mexico. 



Dermatemys wyojiingensis, Leidy. 



Loc. cit. 



From various localities. 



