58G GEOLOGICAL SURVEY OF THE TERRITORIES. 



articular face for the iuner malleolus, terminatiug in a long poiut. The 

 cuboid articular face is quite small aud sublateral, aud sessile like the 

 navicular. Ihe fibular facet is extensive, and the internal lateral well 

 marked. 



On the other hand the coracoid process is produced into a curved 

 hook, and is thus more largely developed than in other Proboscidians 

 or Perissodactyles. The neck is longer than in the other Proboscidians, 

 and the parietal bones appear to be narrowed by the approximation of 

 the temporal fossa, as in the lihinoceros. Almost nothing, however, is 

 known of the structure of the skull. 



The genera are two, as follows : 

 Penultimate molar unlike the last, with external cres- 

 cent and embracing ledge Bathmodon. 



Three molars alike, with two transverse crests not meet- 

 ing within 31etalophodo)i. 



BATHMODON, Cope. 



Proceedings American Pliilosopliical Society, 1872, j). 417. 



This genus was originally chiefly distinguished by the dentition ; at 

 present many other important peculiarities are added. First, as regards 

 the molar teeth ; the two transverse crests I find to be separated (not 

 united) at their inner extremities, by a narrow fissure. The anterior is 

 much the longer, and is curved ; its anterior wall slopes steeply down 

 to the narrow cingulum. The posterior is short and straight, and bears 

 a crest. The numbers are I. 3 ; C. 1 ; P. M. 4 ; M. ? 3. 



The entire mandible presents the following dentition : 1.3; C. 1 ; P. 

 M. 4 ; M. 3. The incisors radiate around the narrow extremity of the 

 trough like symphysis, and have transversely exj>anded crowns. The 

 canine is inclined forward, and forms j)art of the same series. Its crown 

 is triangular in section, the outer face convex. In the males it was 

 enormously enlarged, as indicated by a symphysis in my possession. 

 The anterior premolar approached the canine. The former teeth Ijave 

 an external chevron directed inward, whose extero-superior surface of 

 enamel is acute cordate. Besides this is a little longitudinal ridge, 

 which represents 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 Binothcrium. 



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

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

 atlas has a flat diaparapbi>hysis, presenting its edges fore and aft; the 

 arterial canal traverses it obliquely. The cor«coid is double, having a 

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

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

 bone is narrow pyriform, with two triangular faci^ts on one side, the 

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

 phalanges are very short, somewhat flattened, aud with the terminal 

 portion transverse and rugose as in some toes of Elephm. 



In the remains pertaining to this genus obtained by I^r. Hayden, 

 there are numerous individuals of apparently three species. Two of 

 these are larger and one smaller, the latter in part indicated by an indi- 

 vidual without epiphyses on the lumbar vertebra?. It i)reseuts marked 

 difference in the form of the astragalus atlas, scapula, &c. 



