CHAPTER, Vil 
EUTHERIA—-MARSUPIALIA 
Order I. MARSUPIALIA! 
THE Marsupials may be thus defined :—Terrestrial, arboreal, or 
burrowing (rarely aquatic) mammals, with furry imnteguments ; 
palate generally somewhat imperfectly ossified ; Jugal bone reach- 
ing as far as the glenoid cavity; angle of lower jaw nearly always 
inflected. The clavicle is developed. Arising from the pubes are 
well developed and ossified epipubic bones. Fourth toe usually 
the most pronounced. Teeth often exceed the typical Eutherian 
number of forty-four; molars generally four on each side of each 
jaw. Asarule but one tooth of the milk set is functional, which 
is (according to many) the fourth premolar. Teats lyimg within 
a pouch, in which the young are placed. Young born in an im- 
perfect condition, and showing certain larval characters. There 
is a shallow cloaca. The testes are extra-abdominal, but hang in 
front of the penis. In the brain the cerebellum is completely 
exposed ; the hemispheres are furrowed, but the corpus callosum 
is rudimentary. An allantoic placenta is rarely present. 
Structurally the Marsupials are somewhat intermediate be- 
tween the Prototheria and the more typical Eutheria, with a 
greater resemblance to the latter. 
The name Marsupial indicates what is perhaps the most 
salient character of this order. The pouch in which the young 
are carried is almost universally present. It is less developed 
' Works dealing exclusively with the Marsupials are: Lydekker, in Allen’s 
Naturalists Library, 1894; Aflalo, Natural History of Australia, Macmillan and 
Co. 1896; Waterhouse, Natural History of Mammalia, i. London, 1848; Old- 
field Thomas, British Museum Catalogue of Marsupialia and Monotremata, 1888. 
