DINOCERATA. 571 



do, with the palatine process, a deep, narrow, trench like fossa, which 

 measures almost the entire length of the zygomatic fossae. Processes of the 

 sphenoid contribute to these walls (which are thus double), and the sphenoid 

 roof is strongl}' concave. The alisphenoid is elongate antero-posteriorly, 

 and is principally in contact superiorly with the frontal; anteriorly it has a 

 short suture with the lachrymal. I cannot determine whether the orbito- 

 sphenoid is distinct. Almost its entire length is traversed by a shallow 

 groove, which terminates in a small foramen opticnm, opposite to a point 

 marking the posterior third of the zygomatic fossa. The foramen rotun- 

 dum issues as usual between the alisphenoid and the pterygoid, within the 

 alisphenoid canal, which exceeds it in diameter. 



The lachrymal is a large bone, of a triangular outline, the shorter side 

 being inferior. It is entirely on the inner face of the orbit, and, as in the 

 elephant, separates the frontal and maxillary by its superior prolongation. 

 Its inferior border is slightly notched in front by the large foramen infraor- 

 bitale posferius, and the anterior is deeply emarginate, passing behind the 

 small/ lachrymale. 



The palate is remarkable for its length and narrowness. Its roof is 

 chiefly composed of the maxillaries, but a very short portion is formed by 

 the palatine plates of the o.- o. palatina. These are pi'oduced into a median 

 point behind between the nares, and exteriorly form the inner wall of the 

 postnareal trough for a considerable distance. The maxillaries also form 

 the outer wall for a short distance, being produced in a contracted form 

 behind the molar teeth. The two bones inclose a small foramen in this 

 prolongation, and a larger one on the anterior suture of the palatine, the 

 foramen palatinum. The palate is deeply concave anteriorly. There is an 

 elongate foramen close to the alveolus of the first premolar, extending 

 anterior to it. The premaxillaries are longitudinal and separated anteriorly, 

 for two-fifths of their length, by a large foramen incisivum, which they do not 

 inclose in front. They extend on the side of the muzzle into an acute angle 

 upward and backward, and are prolonged forward above the exterior 

 nares, which the suture reaches by an abrupt descent. The maxillar}^ sup- 

 ports the malar on a posteriorly directed process which reaches to the end 

 of the antei'ior third of the arch below, half that distance on the side, and 



