388 PROCEEDixai^ or the natjoxal museum. vol.49. 



about 44 mm. and are 18 mm. thick. Near the hinder border of the 

 bone is seen the foramen ovale. Just behind this the aUsphenoid 

 sends backward a sphnt of bone against the front of the bulla-hke 

 rjdge, much as is seen in the skull of a cow at hand. Anteriorly the 

 alisphenoid joins the frontal above and the maxilla and the palatine 

 below. The suture with the maxUla appears to be hidden in a deep I 

 fold behind the capsule of the hindermost tooth; and in this fold, too, 

 are concealed the optic and other foramina. 



The palatines are more extensively developed than in Trichecfiits 

 and Halicore. They resemble the same bones in Eotherium. They 

 extend forward to a line joining the front ends of the penultimate 

 molars. Here, taken together, they have a width of 30 mm. Poste- 

 riorly the bones widen, so that at the front of the hinder nares they 

 are 60 mm. wide, while at the middle of the mesopterygoid fossa the 

 distance between their outer borders is 70 mm. As seen when the 

 skull is turned with the palate upward, the hinder branches of the 

 palatines overlap and conceal the edges of the pterygoid processes 

 of the alisphenoid, extending backward nearly to the rear of the 

 basisphenoid. The suture between the palatines and the maxillae 

 are smooth and straight laterally, but in front they are very jagged. 



On account of the advanced position of the external nares, the 

 frontal bones are more normally developed than in probably any 

 other su-enian. From their rear to a line joining their anterior ends 

 is a distance of 148 mm. Posteriorly they fit into a broad notch 

 between the parietals; in front they form a notch for the rear ends 

 of the nasals. Their greatest breadth is at the supraorbital process, 

 and here it is 110 mm. At this place they overlap the lachrymals. 

 The hinder ends of the processes which join the squamosals are 

 97 mm. apart. These processes are 21 mm. wide and extend back- 

 ward from their divergence from the body of the bone a distance of 

 37 mm. The lower border of each process joins the alisphenoid of its 

 side, and the suture can be followed forward until it disappears in 

 the fold between the capsule of the last molar and the body of the 

 frontal. The anterior end of each frontal is truncated. 



The nasals have the anterior end injured, but there is no reason 

 to suppose that they terminate in front in any way different from 

 that seen in Yoshiwara and Iwasaki's specimen. Quite certainly 

 they ended in front in a sharp point a few millimeters behuid the 

 nasal opening. The length of each was close to 100 mm., the greatest 

 width of the two combined is 30 mm. Posteriorly the}'' are enclosed 

 in a notch between the frontals; laterally they unite with the max- 

 illae for a distance of 16 mm.; and for the rest of then' length with 

 the premaxillae. The relations of these bones are not greatly differ- 

 ent from those of an ox, except that they do not come into contact 

 with the lachrymals. 



