EOCENE AND OLIGOCENE TITANOTHEEES OF MONGOLIA 



937 



Type cranial characters. — The type skull is extremely 

 crushed and flattened; the upper facio-cranial portion 

 is distorted to the left, the maxillary portion is dis- 

 torted to the right. This distortion is corrected in the 

 reconstructed figure (fig. 791). The free portions of 

 the nasals measure (ap. by tr.) 169 by 142 millimeters; 



13 2 7 123 



cephaly; the occipital condyles measure 150 millimeters 

 transversely. The hard palate opens into the posterior 

 nares between m^, ml 



Below the incisive border three smaU alveoli may 

 be detected on each side, both crowns and fangs being 

 wanting; the incisors were probably partly vestigial. 



Figure 791. — Cranium and superior dentition of the type of Brontops gobiensis (Am. Mus. 20354, cranium 

 reconstructed after comparison with that of Brontops hrachycephalus) 



A, Cranium in superior aspect. Observe the extraordinarily broad proportions, the indented summits ot the horn cores, the protrusion of the 

 incisive borders indicated by the alveoli of the six incisors. Ai, Palatal view of the type specimen showing the same broad proportions of the 

 cranium; also the reduplication of the premolar cones, deuterocones, and tetartocones, as well as the absence of a hypocone. M, Eight lateral 

 view of the same cranium, displaying the horn cores in lateral aspect, the nasals relatively longer than in B. brachycephalus, and the 

 absence of a postcanine diastema. All one-sixth natural size. 



they are both long and broad. The bony horns rise 

 gradually directly above the orbits from a sloping base 

 (119 mm.) to a height of 53 millimeters and to a width 

 of 57 millimeters. The cranial vertex narrows to 80 

 millimeters between the temporal fossae. The occiput 

 is low and broad, in harmony with the general brachy- 



The approximate measurements of the left canine are, 

 base, anteroposterior 33 millimeters, transverse 25, 

 height of crown 43 (estimated) — obviously a short, 

 obtuse canine. 



Of the superior premolars, p' is very small (ap. 

 18 mm., tr. 15); p^ (ap. 26 mm., tr. 33, estimated) 



