AMERICAN DIPROTODONTS 



129 



is one strong pair, with occasionally one or two rudimentary incisors. 



tor ,/ti. 



FIG. 63. Skull of Wombat (Phascolomys wombat}. (Lateral view.) ang, Angular pro- 

 cess ; cond, condyle of mandible ; ext.atid, opening of bony auditory meatus ; 

 ex.oc, exoccipital ; ju, jugal ; Icr, lachrymal ; max, maxilla ; nas, nasal ; p.max, 

 premaxilla ; sq, squamosal ; ty, tympanic. (From Parker and Harwell's Zoology.) 



The upper canines, if present, are not large. The molars are 



tuberculate or ridged. All Marsupials (ex- ^ 



cept the Wombats) to some extent, and the 



Macropods especially, are characterised by 



the prolongation of the tubes of the dentine 



into the clear enamel. The significance of 



this fact is, however, lessened by the fact 



that the same penetration of the enamel 



by dentinal tubes occurs in the Jerboa, the 



Hyrax, and some Shrews. The feet have 



two syndactylous toes, 1 less marked in the 



Wombats than in the Kangaroos and 



Phalangers. 



This order is mainly Australian at the 

 present day, using the term of course in 

 the " regional " sense (see p. 84) ; the only 

 exception indeed to this statement is the 

 occurrence of the genus Caenolestes in South FlG 64._Bones of right 

 America. But it is now known that Dipro- foot of Kangaroo (Macro- 



L-II *"* i j. J .4.-U I 8 bennetti). a, Astra - 



todont Marsupials formerly existed in the ga i us . c> caicaneum ; 

 same part of the world. <* cuboid : *> * n t- cu - 



. neiform ; n, navicular; 



Fam. 1. Macropodidae. This family //. v, second to fifth toes, 

 contains the Kangaroos, Wallabies, Eat- ( rrom Flower's Osteology.) 

 Kangaroos, and Tree- Kangaroos. With the exception of Dendro- 



1 Except in the South American Diprotodonts. 

 VOL. X K 



I 



