16 
One of these exhibits the following characters: there is a well- 
developed marginal lobe of the posterior cutting edge of the third 
and fourth premolars as well as a low posterior heel, and a rudi- 
ment of an anterior one. The heel of the sectorial is shorter than 
the remaining part of the tooth, and rises to a cutting edge a little 
external to the middle line; there is a small tubercle at its inte- 
rior base. The anterior blade-cusp of the sectorial is much lower 
than the median, which is conical; the two diverge, diminishing 
the shear-like character and action of the tooth. The internal 
cusp is well developed. The first tubercular is of moderate size, 
and is a longitudinal oval in outline. The crown supports two 
low tubercles anterior to the middle, of which the external is the 
larger. The last molar has a single compressed root, and the 
crown is a longitudinal oval in outline. Its position is on the 
ascending base of the coronoid ramus, so that the crown is slightly 
oblique. The masseteric fossa is profound and well defined ; its 
anterior termination is below the middle of the second tubercular 
tooth. The horizontal ramus is not robust, but is compressed, 
and rather deep. 
Measurements of Mandible. M. 
Length along bases of posterior five molars . . 049 
Length of base of fourth premolar ‘ ‘ . lL 
Elevation of crown : : 3 : : . 008 
Length of base of sectorial . : : 5 . .018 
Elevation of crown of : 3 j . 012 
Length of base of first tubercular . : : . 0075 
Width y u bs ‘. 4 . - 0050 
Length of base of second tubercular. : . .0050 
While the characters of this dog do not separate it widely from 
the genus Canis, many of them are quite different from those 
presented by the recent species of the genus with which I am ac- 
quainted. Thus the union of the foramina spheno-orbitale and 
rotunda, the anterior position of the orbits, and the postorbital 
constriction are not seen in the wolf, domestic dog, coyote, jackal, 
or the North American and European foxes. The size of the 
brain was evidently less than in those species, and the sectorial 
teeth quite inferior in the efficiency of their blades. These cha- 
racters may be considered in connection with the low geological 
position of the beds in which the species occurs. 
