THE NATURAL HISTORY OF THE KANGAROO. 
387 
across the loins with tiger-like, black bands (PL CXXVIII. fig. 
4). It is only found in the island of Tasmania, and will probably 
very soon become altogether extinct, on account of its destruc- 
tiveness to the sheep of the colonists. Its teeth have considerable 
resemblance to those of the dog, and it differs from all other 
members of the kangaroo’s order, in that mere cartilages repre- 
sent those marsupial bones which every other member of the 
order unquestionably possesses. 
The last family of the kangaroo’s order consists of the true 
opossum, which (unlike all the animals we have as yet passed in 
review) inhabits not the Australian region, but America only. 
These creatures vary in size from that of the cat to that of 
the rat. 
They are called Didelphidce , and agree with the Dasywridcv 
in having well-developed canine teeth and cutting back teeth ; 
Fig. 15. 
in having the second and third toes free, and five toes to the 
fore foot. But they differ in that — 
(1) Cutting-teeth l 0 (more than in any other animal). 
(2) A large opposable great-toe. 
(3) A tail, naked (like that of the rat) and prehensile. 
One of them is aquatic in its habits and web-footed. Such 
are the very varied forms which compose the six families which 
together make up the kangaroo’s order, and such are the rela- 
tions borne by the kangaroo’s family to the other families of the 
kangaroo’s order. 
But to obtain a clear conception of the kangaroo, we must not 
rest content with a knowledge of its order considered by itself. 
But we must endeavour to learn the relation of its order to 
the other orders of that highest class of animals to which the 
kangaroo and we ourselves both belong, viz. the class Mam- 
malia , which class, with the other classes, Birds, Beptiles, and 
Fishes together, makes up the back-boned or vertebrate primary 
division of the whole animal kingdom. 
What, then, is the relation of the kangaroo’s order — the 
Marsupialia — to the other orders of the class Mammalia ? 
