622 GEOLOGICAL SURVEY OF THE TERRITORIES. 



sixth widens by an inward projection of its border so as to meet the in- 

 tercostal suture between the second and third costal scuta. From this 

 one to the ninth (as far as preserved) the inner margins are produced so 

 far as to make the scuta nearly twice as wide as long, when viewed 

 from above. The first costal is small, its posterior border is curved. 

 The first vertebral is pyriform, truncate in front. It is (perhaps abnor- 

 mally) divided by a transverse suture into a quadrate anterior and 

 cordate transverse posterior portion. The other vertebrals are somewhat 

 longer than broad and are separated by sutures convex anteriorly. 



The intermarginal scuta are all wider than long; their number is nor- 

 mally four, but a narrow one is intercalated behind the inguinal on one 

 side. The longitudinal suture of the acutes of the plastron is exceed- 

 ingly tortuous, winding between jDoints more than an inch apart. The 

 gulars and intergulars are transverse and bounded by transverse sutures. 

 They cross the median suture (which is straight on the anterior lobe) 

 some distance apart. The humerals are long and the humeropectoral 

 scutal suture is convex backward, its extremities reaching the margin 

 in front of the axillae. The anterior extremity of the anterior sternal 

 lobe has a quadrilobate outline. 



The surface is smooth except along the lines of intercostal sutures, 

 where short grooves parallel to the general axis alternate with protu- 

 berances having the same direction, the whole having somewhat the ap- 

 pearance of sculptured characters. 



Measurements. 



M. 



Lengtli carapace (axial) ( 19 inches) ... 0. 500 



Width carapace (axial) (19 inches) 500 



Length of plastron from groin ,. 295 



Width of base anterior lobe 155 



Width extremity anterior lobe (at gnlars) 080 



Length of anterior lobe (at gulars) l'<!3 



Width of unchal scute Oil 



Length unchal scute 024 



Length third marginal 038 



W^idth third marginal . 015 



Width eighth marginal 090 



Length eighth marginal 063 



This species, when compared with its nearest ally, G. imdatum^ differs 

 in the greatly wider marginal scuta; in the latter the corresponding ones 

 (6-7-8-9) are much longer than wide, as in most other tortoises. The 

 intermarginal scuta are of more elongate forms, and the normal number 

 is five in B. undata, instead of four. The sculpture in the longer-known 

 species is entirely distinct, consisting of pits and tubercles scattered 

 generally over the surface, while the peculiar sculpture of the suture 

 lines is wanting. C. hehraicum is relatively wider. 



Bad Lands of Cottonwood Creek. 



Baena undata, Leidy. 



Geological Ssrvey, Montana, 1871, p. 369. 



A partially complete specimen of this species presents the following 

 characters. The anterior lobe of»the plastron is as wide as that of A 

 hebraica, but little more than half as long. The posterior lobe is trun- 

 cate at the extremity. The nuchal scute i^rojects beyond the first mar- 

 ginal ; the reverse is the case in the type of B. hebraica. The posterior 

 sutures of the intergular and gular scuta have a common center, and 

 that of the gular has a rectangular curvature, the nearly transverse 



