THE POUCHED ANIMALS, 243 
number of teeth than all the other known mammals, for 
each half of the lower jaw of the Thylacotherium contained 
sixteen teeth (three incisors, one canine tooth, six pseudo, 
and six genuine molars). If the upper jaw, which is 
unknown, had as many teeth, then the Thylacotherium had 
no less than sixty-four teeth, just double the number 
possessed by man. The Primeval Marsupials correspond, 
on the whole, with the Insectivora among Placental animals, 
which order includes hedgehogs, moles, and shrew-mice. A 
second order, which has probably developed out of a 
branch of the last, consists of the Snouted, or Toothless 
Marsupials (Edentula), which resemble the Toothless animals, 
or Edentata, among the Placental animals by their tube- 
shaped snout, their degenerated jaws, and their correspond- 
ing mode of life. On the other hand, the mode of life and 
formation of the jaws of Rapacious marsupials (Creophaga) 
correspond with those of the genuine Beasts of Prey, or 
Carnivora, among Placental animals. This order includes the 
pouched marten (Dasyurus) and the pouched wolf (Thyla- 
cinus) in Australia. Although the latter attains to the size 
of a wolf, it is but a dwarf in comparison with the extinct 
Australian pouched lions (Thylacoleo) which were at least as 
large as a lion, and possessed huge canine teeth more than 
two inches in length. Finally, the eighth and last order is 
formed by the marsupials with hands, or the Ape-footed 
Pouched animals (Pedimana), which live both in Australia and 
America. They are frequently kept in zoological gardens, 
especially the different species of the genus Didelphys, and 
are known by the name of pouched rats, bush rats, or 
opossums. The thumb on their hinder feet is opposable to 
the four other toes, as ina hand, and by this they are 
