170 THE KANGAROOS. 



the Kangaroos, and was therefore synonymous with 

 the older title, Macropus of Shaw. 



The foremost pair of incisors of the upper jaw, in 

 the true Kangaroos, are arched in front, concave be- 

 hind and broadest and truncated at the apex, and 

 the remaining incisors of the upper jaw are broad 

 and compressed. In M. major (and perhaps some 

 other nearly allied species) the middle incisors on 

 each side of the upper jaw is narrower than the 

 others, and has a vertical groove in the outer side ; 

 the posterior incisor is very broad, being equal in 

 width to the two anterior incisors taken together, and 

 has two vertical external grooves, but in most of 

 the species of Kangaroos the second incisor on each 

 side has no external groove, and the hindermost one 

 has but one of these grooves. The second incisor is 

 always the narrowest, and the hinder one varies in 

 width according to the species. The incisors of the 

 lower jaw are very large, horizontal in their direc- 

 tion, long, compressed and pointed like a lancet, they 

 are slightly broader near the middle than elsewhere, 

 and present each two sharp cutting edges.* The 



* That the inner edges of these teeth should be sharp is re- 

 markable, and the use of this peculiar structure is not evident. 

 I recollect to have read in the work of one of our voyagers, 

 that the great Kangaroo has the power of separating these 

 teeth, and certainly the structure of the lower jaw would seem 

 to permit such a movement ; the symphysis menti in these 

 animals is peculiar, the two rami of the lower jaw meet far 

 back and do not appear to have been strongly attached at the 

 symphysis, but, what is most remarkable, they diverge again 

 at the apex. In the skull of a Kangaroo before me, I find 



