Temnocyon and Hypotemnodon. — Eyernian. 271 
backward to a greater extent and on the whole is more compress¬ 
ed laterally than in the type species; this cone rises from the 
centre of the crown and, in the type species, anterior thereto. 
The deuterocone is well developed only in T.ferox, in the 
type being very minute and placed upon the edge of the crown ; 
nor is there the deep groove or valley separating it from the 
protocone as in T.ferox and T. wallovianus. A minute in¬ 
cipient cone is present only in the former species. The trito- 
cone is more or less flattened in T.ferox , but in the type 
shows a sharper and more marked cutting structure, the sur¬ 
face being highest near the protocone. In T. ferox the sur¬ 
face is nearly horizontal. 
The first superior molar in T. ferox has a very strong cingu¬ 
lum on both the external and (particularly) the internal edges. 
In the other species, however, this development is much less 
marked. The transverse diameter is in all the species very 
considerably greater than the antero-posterior. There is a 
groove between the paracone and the metacone in the several 
species, being greatest and deepest in the largest. In this 
species, too, the two cones show greater lateral compression. 
The protocone is greatest in T.ferox and rises directly internal 
to the groove separating the external cones, whereas in the 
type species it is nearly internal to the paracone. A groove 
or valley separates this cone from the external ones and is 
deepest and widest in T.ferox and in this species the cone is 
more regularly rounded and of a more pyramidal shape than 
in the two smaller ones. A small cone is present at the in¬ 
fernal posterior edge of this groove only in T. ferox. The 
position of forms a characteristic feature of this species. 
In the other Temnocyons the external surface of this tooth 
may be said to form a regular and continuous line with the 
preceding molar, but here the position of this molar is such 
,as to make it join nui (for they are close together) directly pos¬ 
terior to the internal base of the metacone, and the posterior 
edge of this molar forms, with the external edge of rru2, a regu¬ 
lar right angle. The two molars are placed side by side and 
close together throughout, whereas in the type species, they 
touch only at the external edge. The antero-posterior diame¬ 
ters both external and internal are the same in T.ferox , but in 
the type species the diameter of the former is greater than the 
