32 THE AMERICAN MUSEUM .JOURNAL 
portioned, with short heavy limbs and broad blunt-clawed feet. 
It has been thought that Patriofelis was of aquatic habits, and 
more or less nearly ancestral to the Seals; but 1t was more prob- 
ably terrestrial, as its teeth indicate adaptation to flesh food, not 
to fish eating. The limbs and face most nearly resemble those 
of the short-legged Mustelines, otter, mink etc., among modern 
animals, and some of these are aquatic or semi-aquatic; but 
this resemblance may be merely because in both animals the 
limbs are short and heavy. 
Hy 42 NODONTID. 
Types: Sinopa, skull and other parts; Hy@enodon, skeleton and 
skulls. 
Two groups of animals are included in this family, one repre- 
sented by Sznopa, small long-bodied weasel-like animals with 
teeth little specialized, suggesting those of the Opossum, the 
other by Hy@enodon, which was larger, proportioned more like 
the Tasmanian Wolf, with teeth highly specialized for flesh-cut- 
ting. The first group was probably arboreal, the second terres- 
trial in habit. 
In Sinopa, which was characteristic of the Eocene, the crowns of 
the molars are triangular and each has a longitudinal shearing edge 10 
front and one transverse. In Hyenodon of the Oligocene the trans- 
verse shear has disappeared completely, the longitudinal shear is con- 
centrated especially on the third lower and second upper molar, 
the third upper molar has disappeared, and the teeth are as highly 
specialized for flesh-cutting as those of the living Cats. (See Fig. 3.) 
Hyenodon lived during the Oligocene epoch and was the last sur- 
vivor of the Creodonts. In proportions it singularly resembles the 
Thylacine, or Tasmanian Wolf, of the rough bush-land of Tasmania. 
The head is of very large size, with long jaws and large teeth, adapted 
to snapping rather than seizing and holding on to the prey. The 
feet had large, rather blunt claws, not retractile, and the animal 
appears to have walked on the toes, like the dogs and cats, not rest- 
ing the sole on the ground as do the bears. (See Fig. 6.) A finely 
preserved skeleton and several skulls from the Big Badlands of South 
Dakota are mounted in the collection. The largest skull is nearly a 
foot long. 
