4 MACE0P0DIB2E. 



Hind limbs syndaotylous ; the fourth toe very large and with a 

 strong claw ; the fifth similar, but smaller ; the second and third 

 very slender, united ; hallux wholly absent (except in Hypsiprymno- 

 dontince, where it is opposable). Tail long, hairy, sometimes more or 

 less prehensile (naked and scaly in Hypsiprymnodontince). Stomach 

 sacculated. Cseoum present. Pouch large, opening forwards. 



Skull long, smooth and rounded. Nasals nearly always markedly 

 expanded behind. Palatal vacuities generally present between the 

 molars, but often, especially in the larger species, entirely absent. 

 Tip of maxillary zj-gomatic process generally produced downwards 

 as a slender bony process, the infrazygomatic process, often de- 

 scending below the level of the molars ; this process small or absent 

 in the Potoroince, and very variable in its development throughout 

 the family. Bullse variable, either rough and unswollen, or large, 

 bulbous, and transparent; their lower wall running back to and 

 applied against the base of the long paroccipital processes. Mas- 

 seteric fossa of mandible hollowed out below into a deep cavity, 

 walled in externally by a plate of bone, and communicating with 

 the inferior dental canal by a large foramen, through which one or 

 more branches of the inferior dental artery pass outwards into the 

 masseter muscle. ' 



Dentition -.-1. ^, C. lf-^ P.M. y^^, M. M4rlx2=32 



or 34. 



Incisors sharp and cutting, the lower pair often with a scissor- 

 like action with one another, in addition to their cutting-action 

 against the upper ones. Canines small (not equalling i.' in length) 

 or absent above, always wholly absent below. Premolars reduced 

 to two above and below ; and of these the anterior (p.') is always 

 shed with the milk-premolar (m.p.*) at the tooth-change. Molars 

 broad, ridged or bluntly tuberculate, suited for chewing vegetable 

 substances. Series of molars and premolars moving forwards in the 

 skull during the life of the animal, by the absorption of bone in 

 front of, and its deposition behind, their roots ; the rate of motion 

 greatest in the larger species. 



Tooth-change always present ; the milk-premolar well developed 

 and long-persistent, molariform. 



Range. Papuan and Australian subregions. 



Before commencing the systematic study of the Macropodidce, it 

 is absolutely necessary that a clear idea should be gained of the 

 general characters of the dentition, and especially of the manner in 

 which age aifects these characters — subjects worked out in great 

 detail both by Professors Owen and Flower, but constantly neglected 

 by systematic zoologists, for whom these changes are of the greatest 

 importance. 



The full dentition of the members of this family consists, in the 

 upper jaw, first of three incisors, then of a small canine (often, 

 however, suppressed), and then of six cheek-teeth, of which the 

 second in the series is the only one which has a " milk " or deciduous 



