KANGAROOS. 



2 39 



and adapted for cutting. As a rule their upper canine teeth, or tusks, are small, 

 or wanting; and this invariably holds good for those of the lower jaw. As 

 regards their molar teeth, these are invariably characterised by having broad, 

 flattened crowns, surmounted either by tubercles or transverse ridges, and adapted 

 for the trituration of vegetable substances. 



The members of the kangaroo family vary greatly in size, and in the relative 

 length of the hind-limbs, but they are collectively characterised as follows. In the 

 upper jaw there are three pairs of incisor teeth, with sharp and cutting edges ; 

 while the lower jaw is furnished with a large single pair inclining forwards, and 

 sometimes biting against one another 

 with a scissor-like action. The upper 

 canine, or tusk, if present at all, is of 

 small size, as in the accompanying 

 figure ; while there is no corresponding 

 lower tooth. In the adult the cheek- 

 teeth are five in number on each side, 

 of which the first is a premolar ; this 

 condition obtaining in the figured skull. 

 In young animals there are, however, SKULL OF LESUEUR - S RAT . K ANGAEOO. 



two milk -molars in place of this c , tusk, or canine tooth. 



premolar; the number of cheek-teeth 



then being six on each side. The molar teeth themselves may carry either a 

 pair of transverse ridges, or four blunt tubercles. A characteristic feature of 

 the family is to be found in the lower jaw, which has a deep pocket in the outer 

 side of the hinder portion, communicating at its base by a large perforation with 

 the canal on the inner side. The pocket is shown in the accompanying figure, 

 but the communicating aperture is concealed by its outer wall. In all the 

 members of the family the fore-limbs are short and feebly developed, with five 

 complete digits. The hind-limbs, on the contrary, are very powerful, and more 

 or less elongated. Usually they have but four toes, of which the one corre- 

 sponding to the fourth in the typical series of five is much larger than either of 

 the others, and terminates in a huge claw. The outermost toe is considerably 

 smaller, but still stout. The two toes on the inner side of the large one, corre- 

 sponding to the second and third of the typical series, are, however, reduced to 

 small slender rods, lying parallel to one another, and enclosed in a common 

 skin. These rudimental digits are of course useless in progression, and their 

 aborted condition is technically known as syndactylism. The head, especially 

 in the larger forms, is small in proportion to the body, and tapers towards the 

 muzzle. Generally the tail is long, cylindrical, and tapering ; while it frequently 

 aids in supporting the body, and may be prehensile. The female is provided with 

 a large pouch, of which the aperture looks forwards. 



All the members of the kangaroo family are purely vegetable feeders, and are 

 mainly confined to Australia and Tasmania, where, before the introduction of 

 sheep and cattle, they took the place of the ruminants of other regions. They are 

 divided into numerous genera, of which the first includes the true kangaroos 

 and wallabies. 



