33 TAPIROIDA. 
Pachyderms by reason of their vastly superior size, the 
latter also having the two ridges of the grinding surface 
relatively thinner and higher; and limiting the present 
comparison to those molar teeth of the animals more 
nearly equal in size to the species indicated by the fossils ; 
we find that the molars of the Kangaroos, both recent 
and extinct, differ in the longitudinal ridge which unites 
together the two transverse ridges, by crossing the middle 
of the valley; while those of the Manatee have the two 
principal transverse ridges lower and thicker, their angles 
are not bent forward, the posterior transverse basal ridge, 
or “talon,” is relatively larger and higher, the anterior 
talon is wanting, and the fangs descend in parallel lines, 
or slightly converge near their extremities. 
The fossil tooth in question, on the other hand, com- 
bines the more obvious and common character of the 
double-ridged grinding surface with those minor modifica- 
tions, which distinguish the molars of the Tapir from those 
of the Kangaroo and Manatee. Both angles of the ridges 
are slightly bent forwards, making the fore-part of each 
ridge concave; a secondary ridge is continued from the 
outer angle of each of the primary ones, from the posterior 
one to the intermediate valley, from the anterior one to 
the anterior basal ridge, or talon. From this talon a 
ridge extends along the outside of the base of the anterior 
primary ridge, and swells into a small tubercle at the 
outer angle of the middle valley: this little character is 
repeated, also, in the molar teeth of the Tapir; but not 
in those of the Kangaroo or Manatee. Compared with the 
corresponding tooth, viz. the third or fourth molar, right 
side, lower jaw, in the American or Indian Tapirs, the 
following differences are noticeable: the anterior principal 
transverse eminence is relatively smaller in the fossil, and 
