VII AMERICAN DIPROTODONTS 129 
is one strong pair, with occasionally one or two rudimentary incisors. 
ler Ju 
Fic. 63.—Skull of Wombat (Phascolomys wombat). (Lateral view.) ang, Angular pro- 
cess ; cond, condyle of mandible; ezxt.aud, opening of bony auditory meatus ; 
éx.oc, exoceipital ; ju, jugal; cr, lachrymal; maa, maxilla; nas, nasal ; p.maz, 
premaxilla ; sq, squamosal ; ty, tympanic. (From Parker and Haswell’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,’ 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 yy 64, Bones of ripht 
America. But it is now known that Dipro- foot of Kangaroo (Macro- 
todont Marsupials formerly existed in the eee aaa, ot raat j 
same part of the world. ch, cuboid ; ¢, ento-cu- 
Fam. 1. Macropodidae.—This family Gee Re an iees 
contains the Kangaroos, Wallabies, Rat- (from Flower's Osteology.) 
Kangaroos, and Tree-Kangaroos. With the exception of Dendro- 
1 Except in the South American Diprotodonts. 
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