1884.] The Condylarthra. 801 
penultimate milk premolar is more like the corresponding perma- 
nent tooth, but is a little more flattened and elongate, and the 
heel is not tubercular. The first milk molar is a little more com- 
pressed than the corresponding permanent tooth, and the edge of 
the heel is not tubercular. Otherwise they are similar. 
I have dwelt on the characters of this genus more fully than 
on those of some of the others, as it constitutes a type of striking 
importance in the Early Eocene fauna. Its discovery I consider 
to be an impertant event in the history of palzontological 
Science 
But three species of the genus are known thus far, the P. coarc- 
tatus (Pig. 10), P. carinidens and P. rhabdodon Cope. The first two 
-have the jaws and teeth about the size of those of the collared pec- 
cary, while those of the last named are frequently larger than those 
of the white-lipped peccary. In all three speciesthe premolars are 
larger than the true molars. The Periptychus rhabdodon must have 
_ hadapeculiar appearance, and 
one unlike that of any known 
mammal. The long legs with 
plantigrade feet must have 
given it the form of a bear, 
but its very short neck is 
only paralleled by that of the 
elephant. While the shorter 
legs forbid near resemblance 
to that animal, and the shape 
of the head is very different, 
yet the resemblances in the 
` re cannot be overlooked. 
Cast of superior wall of brain-case 
. FIG. 9. a 
had a long tail, stout at a Pevistechas rhabdodon, nat. size. Fig. a, 
animal t was a smaller from above; 4, left side. Origin 
the than the Phenacodus primevus, but the head was of nearly 
Same size. The dental system does not furnish any weapons 
2 of offence or defence, and none are known from any other part of 
a the skeleton. Its large premolar teeth are compressed at the 
. are capable of inflicting a severe bite. ee E 7 
Or cutting flesh or even of crushing bones or other 
4 Substances, Its jas may be supposed to have included sub- 
‘ _ Slances of this character, derived perhaps from both animal and 
“able sources. The Periptychus rhabdodon was the most 
