510 THE WASATCH AXD BEIDGER FAUN^. 



Reptiles than of Mammals, and I have shown that the immovable tibio-tarsal 



articulation is a Reptilian feature as well. These are, however, but hints 



of a relationship doubtless very remote. 



Before proceeding to a more detailed consideration of the genera of 



this order, I give the distinguishing characteristics of the two suborders 



into which they naturally fall: 



I. A third trochauter of the femur, and fossa for the round ligament; no 



alisphenoid canal; superior incisors present . . Pantodonta. 



II. No third trochanternor fossa for the round ligament; an alisphenoid 



canal; no superior incisors .' Diiwcerata. 



The differences presented by these suborders are thus very decided, 

 but they agree in some important points, not necessarily of ordinal value. 

 Thus the foramen ovale is distinct from the foramen lacerum anteritis, and 

 the meatus auditorius is not closed inferiorl}^. In the first point, they agree 

 with Symhorodon and Rhinocerus more than with any Proboscidea or Artio- 

 dactyla. In the latter respect, thej^ agree with the Tapirs and Bhinoceridae, 

 but not with other Ungulates. The cervical vertebrae are short, and not 

 united by ball-and-socket joint, and are intermediate in character between 

 those of Proboscidea and other Ungulates. In both suborders, the scapula 

 is acuminate at its superior border and expanded behind, as in Pro- 

 boscidea, wh;le the abrupt origin of its spine is a character of Proboscidea, 

 Artiodactyla, and many other Mammals, but not of PerissodactyJa. In the 

 rudimental spine and crest of the tibia, we have again especially Probos- 

 cidian resemblances, which are confirmed by the shape of the ilium. This 

 bone expands immediately from the acetabulum into a broad plate, which 

 has a continuous convex crest, and is altogether different from the pedun- 

 culate ilium of the Rhinoceros and Hippopotamus. 



As regards the points in which the suborders difter, it may be observed 

 that the Pantodonta in their dentition and femur resemble the Perissodactyla 

 more than do the Dinocerata, while the absence of alisphenoid canal in 

 Coryphodon is a suilline character, and the only one which I find in the 

 group. In the form of the femur, the Dinocerata resemble closely the 

 Proboscidea, but in the presence of the alisphenoid canal they agree with 

 both Perissodactyla and Proboscidea. It is not unlikely that, in future, 



