PHENACODUS AND THE CREODONTS 203 



the details of its osteology. It was not a large creature (see 

 Fig. 110, p. 196), about 6 feet in length, with a small head. 

 The feet were more or less plantigrade, and five-toed. The last 

 phalanges of the toes show that they carried hoofs and not 

 claws ; yet the fore-feet look a little as if they could be used as 

 grasping organs. The third digit of both hind- and fore-feet 

 exceeds the others, and thus a Perissodactyle-like foot characterised 

 this Eocene creature. The tail is exceedingly long, and must 

 have reached the ground as the animal walked. This is of course 

 by no means an Ungulate character. Still, in the totality of its 

 organisation the animal was decidedly Ungulate, though Professor 

 Cope spoke of Plienacodus as not merely an ancestral Ungulate 

 but as the parent form of Insectivores, Carnivores, Lemurs, Monkeys, 

 and Man himself ! The scapula indeed is from its breadth and oval 

 contour rather like that of a Carnivore. The clavicles as in other 

 Ungulates are absent. The femur is Perissodactyle rather than 

 Aitiodactyle in the presence of a third trochanter. The creature 

 had fifteen pairs of ribs and five or six lumbar vertebrae. The 

 two bones of the leg which lie below the femur are perfectly 

 distinct and separate. A cast of the "brain-case shows that the 

 cerebral hemispheres were smooth and small, the cerebellum of 

 course completely uncovered and nearly as large as the cerebrum. 

 The olfactory lobes were also large. The complete skeleton of 

 Phenacodus has lately been excavated more fully from the 

 enveloping matrix by Professor Osborn,^ and mounted in what 

 is regarded as the natural position of the beast. It appears 

 that though five-toed it went upon the three middle toes only, 

 and furthermore that of these the middle one was the more 

 prevailing, so that Fhenacodus was distinctly " Perissodactyle," 

 at least in habit. Moreover its " long hind-quarters, the long 

 powerful tail . are reminiscent of Creodont ancestry." The 



genus was European and American in range. 



Meniscotherium ( = Hyraco2:is ') comprises several forms of 

 about the size of a fox ; they are both European and American in 

 range. The teeth are more distinctly Ungulate in form than those 

 of Phenacodus, with a W-shaped outer wall. The skull is 

 described as possessing " indifferent, primitive characters," permit- 

 ting a comparison with those of Opossums, Insectivores, and 



1 Bull. Amer. Mus. Nat. Hist. x. 1898, p. 159. 

 ^ Marsh, Amer. Journ. Sci. xliii. 1892, p. 447. 



