342 A MANUAL OF DENTAL ANATOMY. 



condyles, hitherto unknown in Ungulata, and a massive 

 decurved process on each ramus extending downward and 

 outward below the diastema. 



"The position of the condyles was necessitated by the long 

 upper tusks, as, with the ordinary ungulate articulation, the 

 mouth could not have been fully opened. The low position 

 of the condyle, but little above the line of the teeth, is also 

 a noteworthy character. The long pendant processes were 

 apparently to protect the tusks, which otherwise would be 

 very liable to be broken. Indications of similar processes 

 are seen in Smilodon and other Carnivores with long upper 

 canines. With the exception of these processes the lower 

 jaw of Dinoceras is small and slender. The symphysis is 

 completely ossified. The six incisors were contiguous, and 

 all directed well forward. Just behind these, and not 

 separated from them, were the small canines, which had a 

 similar direction. The crowns of the large molars have 

 transverse crests, and the last of the series is the largest." 



It would appear possible that the eminences shown in the 

 figure, and spoken of as " maxillary horn-cores," may be 

 merely the extended sockets of the teeth, which would other- 

 wise have had an implantation inadequate to their length ; 

 they are, however, described as solid, except at their bases, 

 where they are perforated for the fang of the canine tusk, 

 which would look as though they were truly horn-cores ', 

 moreover the Brontotheridae had horn-cores equally peculiar 

 in position (i.e., on the maxillary bones). 



Yet another new order, TILLODONTIA, comprising several 

 genera, has been proposed by Prof. Marsh for the Wyoming- 

 fossil remains, to receive forms which, though not amongst the 

 biggest, are " amongst the most remarkable yet discovered in 

 American strata, and seem to combine characters of several 

 distinct groups; viz., Carnivora, Ungulata, and Rodentia. 

 In Tillotherium, Marsh, the type of the order, the skull has 

 the same general form as in the Bear, but in its structure 



