PALiEOSYOPS LEIDY, AND ITS ALLIES. 
345 
P. paludosus. The occipital contour was probably very similar to that of P. mega- 
rhinus, the posterior portion of the skull rising gradually from between the orbits 
to tbe occipital region. 
Premaxillaries. — The form of the premaxillaries is the most important char, 
acter of the skull of T. cultridens. These bones differ from those of P. paludosus in 
being much higher and more elongated. Their anterior contour is ascending and is 
cut oft' abruptly, so that this portion presents an elongated triangular sj^mphysis 
which articulates with its fellow of the opposite side and has a prominent anterior 
keel. Externally, the superior border of the premaxillaries form an angle with the 
anterior, and this border slopes gradually upward, its posterior limit being above 
the first premolar. The superior border of tbe pi-emaxillaries is more elongate 
in T. cultridens than in P. paludostis owing to the extension of these bones antero- 
posteriorly . When the premaxillaries are viewed from above they present a triang- 
Figuhe 7. — Internal and ventral view of the premaxillary region. 
1,3. Palseosyops paludoms. 2,4. Telmatotlm'iuyn ciiltndens. One-half natural size. 
ular outline, their prominent and elongated median symphysis being conspicuous ; 
their surface on each side of the median keel is concave, but above and below this 
depression- the surface of the bone becomes rounded, and continues the concavity 
as far as the slight diastema between the incisor and canines, where the surface of 
the premaxillaries is slightly concave. The form of the premaxillaries is so char- 
acteristic of this species, that it at once distinguishes it from Palceosyops pahtdosus, 
where these bones are short, rounded and without any anterior keel and have a 
very short, round and slightly oval symphysis. 
Nasals. — The nasals are strongly arched laterally and much elongated, 
their superior surface being convex and narrow; at their junction with 
