31 



another chevron of the true molars. On the first of the latter, both 

 chevrons are developed, the posterior the least, both with their anterior 

 ridge boundaries lowered ; they sink entirely on the last two molars, which 

 become thus two crested as in those of some Tapiroids and the premolars 

 of Dinotherium. 



The sternal segments are cylindric ; in one the articulations for the 

 hsetnpophyses project laterally, giving the piece a T-shaped form. The 

 atlas has a flat diaparapophysis, presenting its edges fore and aft ; the 

 arterial canal traverses it obliquely. The coracoid is double, having a 

 tuberosity on the edge of the glenoid cavity, find a prominent hook just 

 outside of it. The lumbar vertebra are quite short. The cuneiform 

 bone is narrow pyriform, with two triangular facets on one side, the 

 smaller being sublateral ; and one twisted over the other. The ungueal 

 phalanges are very short, somewhat flattened and with the terminal por- 

 tion transverse and rugose as in some toes of Palceytherium. 



In the remains pertaining to this genus obtained by Dr. Hayden, there 

 are numerous individuals of apparently three species. Two of these are 

 larger and one smaller, the latter in part indicated by an individual with- 

 out epiphyses on the lumbar vertebrae. It presents marked difference in 

 the form of the astragalus atlas, scapula, etc. 



a Larger species. 



Astragalus everted in front ; nearly as wide as long ; 

 lower premolars narrower, more elevated and rugose ... B. radians. 



Lower premolar broad, lower, and smooth B. semicinctus. 



an. Smaller species. 



Astragalus much wider than long, decurved in front. . B. latipes. 



BATHMODON RADIANS. Cope. 



Proceedings American Philosophical Society, 1872 (February 16), p. 

 418. Hayden's Geological Survey of Montana, 1871, 350. 



In addition to the characters already assigned to this species as above 

 cited, I add the following : 



The apex of the scapula is a massive flattened acumination with trun- 

 cate extremity. The spine is elevated and truncate next the glenoid 

 cavity, which is a wide oval, much produced at the coracoid margin. 

 The transverse process of the atlas is rounded distally and is about as 

 long as wide ; the surface for the axis is directed obliquely inwards. The 

 fibula has the inner sharp edge prolonged to the proximal end ; the form 

 of the latter is much as in Eobasileus. The astragalus is slightly concave 

 in both directions on the trochlear face, most so antero-posteriorly. 

 The anterior outline of the same is strongly and obliquely convex, and 

 the surface is produced sideways into a latero-anterior apex. The inner 

 malleolar border is thus very concave ; the outer is gently convex with a 

 long fibular facet. The posterior margin concave, the inner tuberosity 



