142 ATJSTEALIAN NATUEAL HISTORY. 



other, and characters concentrated in a few extinct species are 

 still scattered about among the recent genera, each, retaining 

 some peculiarity from tlie Th^ylacoleo, Zygomaturus, Nototherium, 

 or DijDrotodon. 



Fam. Maceopodid^. 



This family comprises the kangaroo tribe, and is another branch 

 or offshoot from the great phalanger family, as I shall presently 

 show. Some of the old fossil kangaroos are chiefly distinguished 

 by having the mandibles closely anchylosed, like the wombats ; 

 their lower incisors small, and not fit, owing to the firmness of the 

 jaw, to nip the grass as modern kangaroos do. On this account 

 they probably succumbed in the battle of life at an early period, 

 whilst the co-existing smaller and fleeter species, who could move 

 rapidly from place to place, lived on till the pi^esent day. The 

 teeth of the kangaroos have always been in number the same as 

 those of the native bear, with this exception, that the iipper 

 canine is seldom develojjed, and that in one group — the kangaroos 

 proper — the grinding teeth are almost lost as quick in front as 

 they came into place behind. Some extinct kangaroos are also 

 distinguished by their thick premolars, but co-existing with these 

 animals were such already as cannot now be separated from the 

 living red kangaroo (Macwjms rufus), or the black wallaroo 

 {Macropus rohustus). The teeth differed as much in shape as 

 they do now. Some exhibited simple lobed grinders, with a con- 

 necting ridge ; others had these lobes strengthened by fangs or 

 buttresses ; others again had teeth like the Diprotodons or 

 Zygomaturi, but all invariably had firmly-rooted grinders, whose 

 fangs expanded below, and thus prevented the perfect and func- 

 tional molar teeth from being easily lost after death. There is 

 nothing so scarce in collections as a perfect fossil kangaroo grinder, 

 and I refer for particulars to the illustrations of our still unpub- 

 lished fossil remains. The tribe of kangaroos is connected with 

 the phalangers proper, through the ring-tail phalangers {T^seudo- 

 cheirus) and the great flying phalangers or petaurista (^Petaiiristd), 

 animals haxiug incisor teeth which above and below resemble 

 those of the Macropodidce. The upper ones, though very small, 

 are of the same shape as the corresponding teeth in the nail-tail 

 wallabies of the genus OnyclwgaJea. 



The connection with the bandicoots, the last of the herbivorous 

 family of Marsupials, is effected through the Hypsiprimni, or 

 short-tailed rat kangaroo, which approach nearest in form to the 

 genus Perameles. 



Fam. Peeamelid^. 

 The bandicoots bridge over the space between the grass and 

 flesh eating tribes. Though they still retain the peculiar hind 

 feet with the two small inner toes, they have developed already 



