MARSUPIATA. 
101 
other external organs, these minute offspring attach themselves to the teats of their mother, 
and remain fixed there until they have acquired a degree of developement analogous to that 
in which other animals are born. The skin of the abdomen is almost always so disposed 
around the mammae as to form a pouch, in which these imperfect young are preserved as in a 
second uterus ; and into which, long after they can walk, they retire for shelter on the appre- 
hension of danger. Two peculiar bones attached to the pubis, and interposed between the 
muscles of the abdomen, support the pouch, [and prevent inconvenient pressure of the young, 
when grown, upon the bowels.] These bones are also found in the male, and even in those 
species in which the fold that forms the pouch is scarcely visible. 
The matrix of the animals of this order does not open by a single orifice into the extremity 
of the vagina, but communicates with this canal by two bent lateral tubes. The premature 
birth of the young appears to depend on this singular organization. The scrotum of the male, 
contrary to what obtains in other quadrupeds, hangs before the penis, which at rest is directed 
backwards. 
Another peculiarity of the Marsupiata is, that, notwithstanding a general resemblance of 
the species to each other, so striking that they were all long included in one genus, they 
differ so much in the teeth, the digestive organs, and the feet, that if we rigidly adhered to 
these characters, it would be necessary to separate them into distinct orders. They carry us 
by insensible gradations from the Carnaria to the Rodentia*y and there are even some animals 
which have the pelvis furnished with similar bones ; but which, being destitute of ineisors and 
even of any sort of teeth, have been approximated to the Edentata, where, in fact, we shall 
leave them, under the name of Monotremata. [The latter are now more properly included 
as a second order of the same superior division of Mammalia which contains the Marsupiata, 
by the general consent of physiologists.] 
In brief, it may be stated that the Marsupiata form a distinct class, parallel to that of 
ordinary quadrupeds, and divisible into similar orders ; so that, if we were to arrange 
these two classes into even columns, the Opossums, Dasyures, and Bandicoots, would be 
opposed to the insectivorous Carnaria, such as the Tenrecs and Moles ; the Phalangers 
and Potoroos to the Urchins and Shrews ; while the Kangaroos, properly so called, could not 
well be compared with any other genus; but the Wombat should be placed opposite the 
Rodentia. Lastly, if we were to consider the bones of the pouch only [commonly desig- 
nated marsupial bones], and regard as marsupial all animals which possess them, the 
Platypuses and Echidnas might compose a group parallel to the Edentata. 
Linnaeus ranged all the species which he knew under his genus Didelphis, signifying double 
matrix. The pouch is indeed in some respects a second one. 
[The Marsupiata, together with the Monotremata, is now generally regarded as a distinct 
subclass, Ovovivipara, equivalent to the rest of the Mammalia. Its members are lower in 
their organization than any other mammiferous animals, approximating the oviparous type 
(and particularly Reptiles), in sundry details of their organization. The hemispheres of the 
brain, for instance, (which is much reduced in size,) are not united by a corpus callosum j 
and they are observed to be very defective in intelligence, as is indicated by their phy- 
siognomy t : the blood also is returned to the heart by two principal veins, as in Birds 
and Reptiles; and the sutures of the skull never become united. In short, they hold an 
analogous relation towards other Mammalia, to that which the Batrachia present to all 
other Reptiles. Their incisor teeth frequently exceed six in number, which is the maxi- 
mum throughout the rest of the class, — another indication of their inferiority. 
The geographic range of the Marsupiata, with the exception of the Opossum group 
peculiar to America, is at present almost confined to Australia and the neighbouring coun- 
* Only upon the supposition that the gnawing- teeth of the Rodentia I supiata, is afforded by their turning to bite the stick with which they 
are modified incisors, which is more than doubtful. — E d. I are smitten, rather than the hand that guides it. 
t A curious illustration of this inferiority on the part of the Mar- I 
