7 
tooth, one well-known in the typical genera of Viverride and Mustelide. 
Temnocyon is, however, truly canine in other details, and appears to ap- 
proach the genus Paleocyon of Lund. According to this author, the 
posterior inner tubercle of the anterior part of the crown of the sectorial 
tooth is wanting in that genus, so that it is distinct from the North Ameri- 
can form. 
Specif. Char. The mandibular ramus is rather deep and compressed, 
much more so than in the Canis latrans, with which it agrees in the length 
of the dental series. As compared with the existing species of Canis and 
Vulpes of North America, the sectorial tooth is relatively smaller and the 
premolars larger. In this respect it agrees with most other dogs of the 
Lower Miocene, and differs from those of the Upper Miocene (Loup Fork).* 
The posterior tubercle is wanting from the premolars, excepting the last, 
where it is large and obtuse, differing in this respect also from most recent 
dogs, and from the cotemporary Canis gregarius. In the sectorial tooth 
the principal cusp is much clevated above the anterior, while the inner 
median is small, with its apex in line with the anterior. The cutting edge 
of the heel is not acute, and is a little external to the median line ; there is 
a weak cingulum-like angle at its inner base. The first tubercular tooth is 
large, nearly equaling in antero-posterior diameter the base of the third 
premolar. It is parallelogrammic in transverse section, and supports two 
principal cusps and an anterior ledge. The cusps are pronounced and 
stand exterior to the middie line; their inner side slopes to the base of 
the crown where there is no cingulum. The ledge is higher on the inner 
than the external side. There are no basal cingula on either side of the 
bases of any of the teeth. The second tubercular molar is lost. 
The alveolar margin of the jaw rises behind the sectorial tooth, and the 
inferior margin begins to ascend below the middle of the same tooth more 
decidedly than in C. lupus, latrans or cuspigerus. The two large mental 
foramina, are situated, the one below the second, the other below the third 
premolars. 
Measurements. M. 
Length of anterior six molars.......-..-. 0... sees eee ee 078 
by ns fou) 2 osecaulisouiene ceectheneeee 045 
#8 pase of second premolar.............0.6.50 O11 
Elevation of crown ‘“ sO) “EPS E ea segaa Meee O11 
Length of base of fourth Se Se Awudeacensecu eee mrae O15 
Elevation of crown “ SES heenaunas Sees Gia dbu ac paanuan .014 
Length of base of sectorial tooth...............-++4ee- 0185 
Elevation of principal cusp of sectorial tooth ......... .0160 
ee anterior ae - tO egee eee a 009 
Length of heel of sectorial.............---. 0. eee ee eee 007 
Elevation ss WO _eipiaa Reart EMA 2 aaah acatei aba eagie es 0085 
Length of crown of first tubercular..........0+-+.----. 0115 
% See Proceedings Academy Philadelphia, 1875, p. 22, where I have discussed 
the origin and history of the sectorial tooth. 
