14 THE AMERICAN MUSEUM JOURNAL 



portioned, with short hea\'y limbs and broad blunt-clawed feet. 

 It has been thought that F\itriojelis was of aquatic habits, and 

 more or less nearly ancestral to the Seals ; but it 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^nodontid^. 



Types: Sinopa, skull and other parts; Hyccnodon, skeleton and 

 skulls. 



Two groups of animals are included in this family, one repre- 

 sented by Sinopa, small long-bodied weasel-like animals with 

 teeth little specialized, suggesting those of the Opossum, the 

 other by Hycenodon, 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 in 

 front and one transverse. In Hyccnodon 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.) 



Hycenodon lived during the Oligocene epoch and was the last sur- 

 vivor of the Creodonts. In proportions it singularly resembles the 

 Thvlacine, 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. 



