MARSUPIALS AND MONOTREMES 341 
THE SELVA. 
South America has one other marsupial—the Selva—an animal which, while possessing the 
dimensions and much of the aspect of an ordinary rat, is remarkable as differing so materi- 
ally in the character of its teeth and other structural points that it cannot be referred to any 
existing marsupial family. On the other hand, this type is found to coincide in the above par- 
ticulars with species hitherto only known in the fossil state, and excavated from the same ter- 
tiary deposits in Patagonia which have been productive of the distant ally of the Tasmanian 
wolf. It is yet hoped by zoologists that the discovery of other interesting and possibly some 
supposed extinct mammals may reward the thorough exploration of the vast South American 
forests. The capture in the flesh of some form allied to the huge ground-sloths, such as the My- 
lodon and Megatherium, is, howéver, now considered to be quite beyond the pale of possibility. 
MoNoTREMES, OR EGG-LAYING MAMMALS. 
With this group or order of the Mammalian Class we arrive, as it were, on the border- 
land between the more typical Mammals and Reptiles. In the last group, that of the Mar- 
supials, it was observed that the young were brought into the world at an abnormally early and 
helpless phase of their existence, and usually consigned, until able to see and walk, to a variously 
‘modified protective pouch. With the Monotremes a yet lower rung in the evolutional ladder is 
reached, and we find that the young are brought into the outer world as eggs, these being in the 
one case deposited in a nest or burrow, and in the other carried about by the parent in a rudi- 
mentary sort of pouch until they are hatched. 
The living representatives of this singular mammalian order are but few in number, being 
restricted, in point of fact, to only two distinctly differentiated family types—the Echidna or 
Porcupine Ant-eater, and the Platypus. These monotremes, moreover, like the majority of 
the existing marsupials, are limited in their distribution to the Australasian region. The 
single species of the Platypus is only found in Tasmania and the southern and eastern 
districts of the Australian Continent, while the Echidna numbers some three recognised species, 
two of which belong to Australia and Tasmania and the third to New Guinea. 
Tue EcHIDNA. 
The Ecuwwna, Porcupine ANT-EATER, or “PORCUPINE,” as it is commonly called by the 
Australian colonists, would seem at first sight to represent an animal in which the characters 
of the hedgehog and the common porcupine are interblended, the innumerable spines being 
longer than those of the former, but less in length than those of the last-named animal. The 
head, with no externally visible ears and remarkable elongated beak-like snout, however, at 
once proclaims it to be altogether distinct from these. The animal has no teeth, and the 
tiny mouth at the termination of the beak-like snout simply constitutes an aperture for the 
extrusion of the worm-like glutinous tongue, wherewith, after the manner of the true ant-eaters, 
it licks up the inhabitants of the ants’ nests upon which it feeds. For tearing down the 
ants’ nests and obtaining its customary food, as also for its inveterate burrowing propensity, 
the feet, and more especially the front ones, are provided with strong, blunt, and very powerful 
claws. The male animal is in addition armed on the hind feet with a peculiar supplementary 
spur, which is, however, still more conspicuously developed in the platypus. 
Three distinct species of the echidna are recognized by zoologists. The one peculiar to 
the cooler climate of Tasmania is remarkable for its more slender spines, the much greater 
abundance of the long bristle-like hairs, and the thickness of the seal-brown under-fur, as 
compared with the typical Australian form. In North-west New Guinea the largest and most 
aberrant form is met with. Normally it has only three toes in place of five to each foot, 
the spines are very long and thick, the body is deeper and more compressed, and the animal 
stands comparatively high upon its feet. 
