THE TERTIARY PERIOD. 229 



present in numbers proportionate 'to the herbivorous animals. 

 Among these the most blood-thirsty were the Hycenodkntidce. 

 They were first described from the Miocene of France by Cuvier 

 under another name. Subsequently four additional species were 

 found and described by De Laizer and De Parieu under the above 

 family name. The three distinct species found in the Bad Lands 

 by Evans, Shumard, Meek and Hayden were described by Leidy. 

 <c The genus HyaenJdon combined the characters af the wolf, tiger, 

 hyaena, weasel, raccoon and opossum." (Leidy). It was, therefore, 

 one of the most comprehensive types of carnivorous mammalian ani- 

 mals that ever existed. The largest of the species was M. horridus, 

 and was about the size of the largest of the black bears. The den- 

 tition of this animal was the most formidable conceivable. " In 

 addition to powerful canine teeth, three of its molars were structured 

 after the single sectorial tooth of other carnivorous mammals, 

 though the last alone reached the full development of the corres- 

 ponding tooth of the latter. The last of the series of molars were 

 formed like those of the lion and tiger. These teeth the strongest 

 and broadest combined the mechanism of the wedsre and scissors, 



o 



and were eminently adapted for cutting tissues and bones. Im- 

 mense temporal fossa3 occupied the sides of the skull for the attach- 

 ment of the powerful muscles that operated the levers that moved 

 the lower jaw. The skull was about a foot in length. No animal 

 living contemporaneously with this formidable creature could have 

 resisted its power." (Leidy.) Next in size was M. cruentus, and 

 smallest was M. crucinus. 



Among the carnivora of the Nebraska Miocene the cat family 

 (Felidce] were well represented. Among the most remarkable of 

 the family was a genus of saber-toothed lions (Drepanodori). Its re- 

 mains were first found in Western Europe, afterwards in Greece 

 and Asia, and finally in both Americas. The largest species equaled 

 the lion and tiger in size, and judging from their terrible array of 

 destructive teeth were even of greater ferocity. In comparison 

 with the existing cat family they were characterized by a greater 

 proportionate size and flattened form of the upper canine teeth, 

 which has given these animals the name which they bear. Dre- 

 panidon occidentalis was about the size of the existing panther. 

 D. primaBvus was slightly smaller. Two of the skulls found by 

 Hayden exhibit marks of a conflict with some other carnivorous 

 animal and probably the largest HyaenJdon, as the canines of the 



