CREODONTA. 359 



especially the part pi-otruded beyond the alveolus. The crown is stout at 

 the base, but is soon compressed and obliquely truncated by the attrition of 

 the inferior canine on its inner face. Two superior molars preserved are 

 three-rooted, and the section of the crown is more or less equally trilobate. 

 The number in the maxillary bone is estimated at seven, the number found 

 in the ramus of the mandible. There are six two-rooted molars below, and 

 probably one single-rooted premolar, though this is indicated by an alveolus 

 only. The molars are rather narrow anteroposteriorly, and are not very 

 different in size, except that the penultimate is a little longer, and the last a 

 little shorter than the others. There was evidently a longitudinal cutting- 

 edge behind, and some other shorter process on the front of the ci'own ; the 

 edge is preserved on the last tooth and resembles that of M. obtusidens, so 

 that I have little doubt that the remainder of the tooth was, as in that 

 genus, a conic tubercle. This opinion, based on my imperfect specimen, is 

 shown to be correct by the Princeton specimen. Here the teeth are as in 

 M. obtusidens. The most remarkable feature of the genus is seen in the 

 inferior canines. These are very large teeth, and are directed immediately 

 forwards, as in the case of the cutting- teeth of rodents. They work with 

 their extremities against the retrorse crowns of the two external incisors 

 above, and laterally against the superior canine. They are separated by a 

 space about equal to the diameter of one of them. In this space I find no 

 alveoli nor roots of teeth; the outer alveolar wall extends far beyond the 

 inner. The latter terminates opposite the middle of the superior canine. 

 It may be that there are no inferior incisors. 



Some of the vertebrae display stout triangular neural spines ; on the 

 lumbars the posterior zj'gapophyses are embraced laterally by the grooved 

 correspondents of the succeeding vertebra. Some of the caudal vertebrae 

 are long, slender, and without neural arch, indicating that this genus, like 

 3£. obtusidens, had a long, slender tail. 



Measurements. 



M. 



Length of glenoid cavity 045 



Width of glenoid cavity 025 



Diameter of zygomatic fossa 05S 



Width of opisthotio inside foramen stylohyoideum 01 i 



Diameter of meatus auditorius extemua 012 



Diameter of cavum tympani 009 



