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 dcvelopement 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 tliose 

 sjjecies in which the fold that forms the jiouch 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 du-ected 

 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 

 diff"er 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*, and there are even some animals 

 which have the pelvis furnished with similar bones ; but which, being destitute of incisors and 

 even of any sort of teeth, have been approximated to the Edentata, where, in fact, wc 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 jiammalia which contains the Marsupiata, 

 by the general consent of physiologists.] 



In brief, it may be stated that the Marsvpiata 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 

 oj)posed to the insectivorous Carnaria, such as the Tenrecs and Moles ; the Phalangers 

 and Potoroos to the Urchins and Shrews ; while the Kangaroos, projjcrly so called, could not 

 w ell be compared with any other genus ; but the Wombat should be {ilaced o])posite 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 ovip.arous 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 ; 

 and tb.ey 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- 

 nuim throughout the rest of the class, — another indication of their inferiority. 



The geographic range of the Marsupiata, with the exception of the 0])ossum group 

 peculiar to America, is at present almost confined to Australia and the neighbouring coun- 



• Only upon the sappositiou that the gnfuving; teeth of Iht Rudcutin | su/i'al'i, is alTorded by their lurniii),' to bite ;lie stitli with nhicli they 

 lire iiioiiifieii incisors, which is more than doulnful.— SId. are !^mitleu, rather than the hand that guides it. 



t A curious illuslriition of this inferiority on the part of the Mar I 



