556 GEOLOGICAL SURVEY OF THE TERRITOEIES. 



be determined, but projecting .25 incli be;vond tlie alveoli tliey are com- 

 l)ie.ssed, the large outer tooth with a longitudinal angle in front. 



The mandibular rami are quite elongate, and indicate a cranium near 

 the size of that of the brown bear, ( Uraus arctofi.) Their form is slender, 

 and they have a long, rnther narrow, symphysis, whi(;h projects obliquely 

 forwards. The angle is not preserved. The mental foramen is large and 

 issues just behind the canine teeth. 



The dentition is I. :^ ; C. ^ ; M. ^|. The canine is of very large size, 

 especially the part protruded beyond the alveolus. The crown is stout 

 at the base, but is soon compressed and oblifpiely 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 Ibund in the ramus of the maudible. 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 antero-posteriorly, and are uot very dift'ereut 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 crown; the edge is pre- 

 served on the last tooth and resembles that of Mesonyx^ so that I have 

 little doubt that the remainder of the tooth was, as in that genus, a conic 

 tubercle. The most remarkable feature of the genus is seen in the 

 inferior canines. These are very large teeth, and are directed immedi- 

 ately 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 iiud 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 vertebrai display stout triangular neural spines ; on the 

 lumbars the posterior zygapophyses 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 Mesonyx^ had a long, slender tail. 



Affinities. Having described the available parts of this form, it re- 

 mains to consider its place in the zoological system. The structure of 

 the dentition of the upper jaw, with the mode of articulation of the mau- 

 dible, removes it from such orders as llodentia and Edentata. The only 

 remaining ones with which it is necessary to compare it are the Fcris- 

 sodiictyla, Frohoscidia, and Carnivora. As many of the diagnostic bones 

 are wanting, it is necessary to rely on collateral and empirical indica- 

 tions of relationship. From tapiroid types the development of the 

 tympanic region distinguishes it. From Proboscadians the slender feet 

 and reduced ulna, as well as the longitudinal crests of the teeth separate 

 it. It then remains to compare it with rcrissodacfylcs of the types which 

 possess strong canine teeth. In points of resemblance to these we have 

 the flat claws and separate scaphoid and lunar bones; nevertheless the 

 greater number indicate truer afiinity to the Carnivora. Such are the 

 external transverse glenoid cavity, the teeth with longitudinal crests, 

 the slender digits, the well-developed tympanic bone; confirmatory are 

 the large canine teeth, the incomplete orbit, and the projecting inner 

 condyle of the humerus. The foru) of the claws is not absolutely in- 

 compatible with the same order, as it is approximated by some of the 

 Seals. 



