64 MACROPODIDiB. 



about the cKffs with remarkable agility. Their long bushy tails 

 are used as balancers, and are not therefore thickened and strength- 

 ened for use as a third support, as is the case with the ordinary 

 Wallabies. 



Synopsis of the Species. 



I. External Chakactees. 



A. Tail annulated with brown and pale yellow. 

 a. A dark nuchal stripe present. Ears, uniform 



yellow behind ; 1. P. xanthopus, p. 64. 



B. Tail unannulated, darkening towards end. 



6. Back of ears grey at base, brown or black 



for terminal half. A black occipital streak. 



a'. Tail nearly aU black. Occipital streak 



not extending down neck. E. Australia 2. P. penicUlata, p. 66. 

 6^ Tail about hdf black. Occipital streak 

 passing down neck to centre of back. 



W. Australia 3. P. lateralis, p. 68. 



c. Back of ears uniform grey or fawn, some- 

 times tipped with white. No occipital or 

 nuchal streak. 



c^. Shoulder-markings present 4. P. hrachyotis, p. 69. 



d'-. No shoulder- or flank-markings present, 

 o'. Size medium ; hind foot about 130 mil- 



lim 5. P. inornata, p. 70. 



6". Size very small ; hind foot about 100 



mjllim 6. P. concinna, p. 71. 



II. Cranial Chabactees. 



A. Length of skull, when adult, more than 90 



millim. 

 a. Muzzle broad, its sides and the interorbital 



region inflated. Greatest breadth of nasals 



about one third their length 1. P. xanthoptts, p. 64. 



6. Muzzle narrow, neithejr its sides nor the 



interorbital region inflated. Greatest 



breadth of nasals about one fourth their 



length 2. P.pemcillata, p. 66. 



B. Length of skull between 80 and 90 millim. 



c. Frontal outline concave above front of orbit. 



Nasals little expanded behind 3. P. lateralis, p. 68. 



d. Erontal outline convex or straight above 



front of orbit. Nasals expanded behind, 



as in PI. Xn. fig. 2 4. P. brachyotis, p. 69. 



C. Length of skull less than 76 miUim. 



e. Nasals much expanded behind 6. P. concinna, p. 71. 



D. Cranial characters unknown 5. P. inornata, p. 70. 



1. Petrogale xanthopus. 



Petrogale xanthopus. Gray, P. Z. S. 1854, p. 249, pi. xxxix. (animal) ; 

 Gould, Mamm. Austr. ii. pis. xliii., xliv. (animal) (1865) ; Gerrard, 

 Cat. Bones Mamm. B. M. p. 128 (1862) ; Erejft, Austr. Vert, 



