1884. | The Creodonta. 255 
rent sucking apparatus in the body, and the only use I can assign 
to the structure just described, is that of a pumping organ. It is 
probable that the liquid food is sucked into the pharynx by the 
contraction of the muscles which are attached to the chitinous 
threads ; this process enlarges the pharynx cavity by lifting the 
roof, From the pharynx the food passes, by muscular contrac- 
tion, down the cesophagus. [Plates to follow with succeeding 
number. | 
(To be continued.) 
Faw 
À 
THE CREODONTA. 
BY E. D. COPE. 
Eeen knowledge justifies the generalization that, since 
‘the Eocene period, the mammalian fauna of the Northern 
hemisphere has diminished in the number of its species and gen- 
era. The Eocene fauna was richer than the Miocene ; the Miocene 
than the Pliocene, and the Pliocene was richer than the modern 
_ fauna. With this numerical diminution in species has come in- 
creased specialization of structure, which means both greater per- 
fection of mechanism and greater diversity of type.” 
_ The order of Carnivora is a universal and well-known factor of 
the mammalian life of the present period. It was equally so in 
the Pliocene and Miocene periods. When we come to examine 
the overflowing life of undoubted Eocene time, we can no longer 
find mammals which possess the essential characters of the order. 
¢ Carnivora are unguiculate gyrencephalous mammalia with a 
Soossified scaphoid and lunar bone of the carpus, called, there- 
» the scapholunar bone. They have a grooved astragalus. 
No scapholunar bone has yet been found in any Eocene mammal 
_ ' North America, and it is doubtful whether any has been found 
in Europe. Nevertheless the Eocene fauna did not lack preda- 
tory flesh-eaters whose function was like that of the Carnivora of 
“er periods, to restrain the undue increase of all other forms of 
life. Their variety was greater than that presented by their car- 
nivorous Successors on the North American continent, and their 
numbers were proportioned to the general luxuriance of the life 
which furnished them subsistence. There were species whose 
“ze and powers of destruction equaled those of the bears, lions 
| = tigers of modern times. Species of medium size abounded, 
.., Seneralization was published in the Report U. S. G. G. Survey W. of tooth 
