CHAPTER XXII 
MARSUPIALS AND MONOTREMES 
BY W. SAVILLE-KENT, F.L.S., F.Z.S. 
MARSUPIALS 
ITH the order of the Pouched Mammals we arrive — with the exception of the Echidna 
and Platypus, next described — at the most simply organised representatives of the 
Mammalian Class. In the two forms above named, egg-production, after the manner 
of birds and reptiles, constitutes the only method of propagation. Although among marsupials 
so rudimentary a method of reproduction is not met with, the young are brought into the 
world in a far more embryonic condition than occurs among any of the mammalian groups 
previously enumerated. There is, as a matter of fact,’an entire absence of that vascular or blood 
connection betwixt the parent and young previous to birth, known as placentation, common 
to all the higher mammals, though certain of the more generalised forms have been recently 
found to possess a rudiment of such development. In correlation with their abnormally 
premature birth, it may be observed that a special provision commonly exists for the early 
nurture of the infant marsupials. In such a form as the Kangaroo, for example, the young 
one is placed, through the instrumentality of its parent’s lips, in contact with the food-supplying 
teat, and to which for some considerable period it then becomes inseparably attached. Special 
muscles exist in connection with the parent’s mammary 
glands for controlling the supply of milk to the young 
animal, while the respiratory organs of the little creature 
are temporarily modified in order to ensure unimpeded 
respiration. The fact of the young in their early life being 
commonly found thus inseparably adhering to the parent’s 
nipple has given rise to the fallacious but still very widely 
prevalent idea among the Australian settlers that the 
embryo marsupial is ushered into the world as a direct 
outgrowth from the mammary region. 
At the present day, with the exception of 
the small group of the American Opossums and 
the Selvas, the entire assemblage of marsupials, 
comprising some 36 genera and 150 species, 
are, singularly to relate, exclusively 
found in Australia, New Guinea, and 
the few neighbouring islands recog- 
nised by systematic zoologists as 
pertaining to the Australasian 
region. What is more, this region 
of Australasia produces, with some 
few insignificant exceptions, chiefly 
rodents, no other indigenous 
mammals. Photo by Billington] 
[ten nstand 
It is interesting to note that P fi Die aerain ae ae ts 
s * . . . . n peneral form ‘00S are SO one another that one ure Would almost serve 
within the limits of this isolated . . ‘frail . 
308 
