134 NAIL-TAILED WALLABY CHAP. 



by Banks. It is said that 15 or even 20 feet are covered at 

 a bound, and in bound after bound. But in walking slowly it 

 can be readily seen from an inspection of Kangaroos at the 

 Zoological Society's Gardens that the animal does rest upon its 

 tail, which with the hind-legs forms a tripod. 



Petrogcde with six species comes next to Macropus, and is 

 indeed only to be differentiated from it by the thickly-haired 

 and more slender tail, which is not used, as it is sometimes in 

 the Kangaroos, as an extra hind-limb. The Kock-Kangaroos live 

 among rocks, which they climb, and from which they leap ; and 

 the tail acts rather as a balancing pole. The most elaborate 

 account of the anatomy of Petrogale known to me is by Mr. 

 Parsons. 1 The dentition as given by Mr. Thomas is I ^ C {} 

 Pm ^ M ^ that of Macropus without the occasionally occurring 

 canine of the upper jaw. The osteological characters which 

 separate it from Macropus are quite insignificant. Mr. Parsons 

 mentions a wormian bone, " os epilepticum," at the junction of 

 the coronal and sagittal sutures. It was found to occur in two 

 out of five skulls examined, and appears not to occur in other 

 Kangaroos. The palatine foramina of Petrogale are so large that 

 the posterior part of the bone is only a narrow thickened ridge. 

 The small intestine of P. xanthopus is 102 inches long, the 

 large intestine 44 inches. The caecum has a length of 6 inches, 

 and is not sacculated, differing in this from the caecum of 

 Macropus major. The best known species are P. xanthopus and 

 P. penicillata. The genus is confined to Australia itself, and 

 does not enter Tasmania. 



Onychogale includes the so-called "Nail-tailed Wallabies," which 

 have a thorn at the end of the tail, reminding one of the Lion and 

 the Leopard, whose tails have a similar armature. The muffle is 

 hairy. Three species are allowed by Mr. Thomas. 



Lagorchestes has, like the last genus, the rhinarium, i.e. that 

 part of the nose immediately surrounding the nostrils, hairy 

 instead of smooth as in the Kangaroos proper. It is distinguished 

 from Onychogale by the absence of the terminal callosity to the 

 tail, which is rather short. The name Hare-Kangaroo is given 

 to the members of this genus (three species) on account of 

 their exceeding fleetness. This genus is limited to Australia 

 itself. L. conspicillatus is said to present " a remarkable resem- 

 1 Proc. Zool. Soc. 1896, p. 683. 



