456 HYAENODON AND PATRIOFELIS CHAP. 



long, and the top has a great sagittal crest. The paroccipital 

 processes are short and are closely applied to the mastoid processes. 

 The mesethmoid is larger than in the carnivorous Marsupials, and 

 the frontals are very large. The palate has a peculiar structure ; 

 in most species the hinder ends of the palatines are separated 

 by a narrow fissure which broadens gradually, thus forming the 

 posterior nares. In H. leptocephalus the posterior nares are brought 

 very far back by the meeting of the alisphenoids. The pre- 

 sphenoid, contrary to what we find in the Dog, for example, is 

 chiefly concealed by the vomer, which covers it. The mandible 

 has a long and strong symphysis, and its angle is not inflected. 

 The fore-limb is described as being " weak when compared with the 

 modern Carnivora." The scaphoid and lunar are separate, and 

 there is a centrale. The teeth present us with nearly the typical 

 formula. There is only one molar missing in the upper jaw. The 

 canines are enlarged. It has been suggested from a consideration 

 of its palate that Hyaenodon was a semiaquatic animal ; the 

 deep cleaving at the extremities of the phalanges seems to point 

 in the same direction, since they resemble in this the genus 

 Patriofelis, which there are other reasons to regard as aquatic. 

 This latter genus has a fore-limb which is very like that of the 

 Pinnipedia, the digits are much spread out, and would seem 

 to have supported a kind of paddle. In any case it certainly 

 fed upon aquatic tortoises, for their remains have been found in 

 its coprolites. The name Limnofelis, also applied to what appear 

 to have been members of this genus, is suggestive of their habits. 

 Patriofelis, at least one species, seems to have been of about the 

 size of a Lion. 



Mesonyx has a brain case which is actually smaller than that 

 of the Marsupial Thylacinus. The lachrymal bone is very large, 

 and extends a little way over the face, as is also the case with 

 Hyaenodon ; this condition is also found in Insectivora and in 

 Thylacinus. The axis vertebra has a curiously-shaped spine, 

 which is very different from the hatchet-shaped process of that 

 vertebra usual in the Carnivora, but is not unlike what exists 

 in the Arctoid genera Meles and Mydaus. The limbs show 

 much disparity in length, and seem to argue a much -arched 

 back when the creature progressed. The carpus is stated to 

 be strikingly like that of the Insectivora. There is as in 

 other Creodonts a separation between the scaphoid and lunar; 



