MARSUPIALIA. 529- 



and E. setosa, both belonging to the Australian province. The 

 Echidna hystrix is the best-known species, and in some exter- 

 nal respects is not unlike a large hedgehog, having the back 

 covered with strong spines, interspersed with a general coating 

 of bristly hairs. The snout has not the form of a duck's bill, 

 as in the Ornithorhynchus, but the two mandibles are greftly 

 elongated, and are enclosed in a continuous skin till close 

 upon their extremities, where there is a small aperture for the 

 protrusion of a very long and flexible tongue. The jaws are 

 wholly devoid of teeth or anything in the place of teeth ; and 

 the nostrils are placed at the extremity of the cyhndrical snout. 

 The feet have five • toes each, furnished with strong curved 

 digging-claws, but the toes are not webbed. The Echidna 

 measures from fifteen to eighteen inches in length, and is a 

 nocturnal animal. It lives in burrows, and feeds upon insects, 

 which it catches by protruding its long and sticky tongue. 



Order II. Marsupialia. — The order Marsupialia con- 

 stitutes by itself the sub-class Didelphia, and forms with the 

 Monotremata the division of the Non - placental Mammals. 

 With the single exception of the genus Didelphys, which \z 

 American, all the Marsupialia belong to the Melanesian pro- 

 vince ; that is to say, they all belong to Australia, Van Die- 

 men's Land, New Guinea, and some of the neighbouring 

 islands. * 



The following are the characters which distinguish the 

 order : — 



The skull is composed of distinct cranial bones united by 

 sutures, and they all possess true teeth ; whilst the angle of 

 the lower jaw is almost always inflected. The pectoral arch 

 has the same form as in the higher Mammals, and the cora- 

 coid no longer reaches the anterior end of the sternum. All 

 possess the so-called "marsupial bones," attached to the brim 

 of the pelvis. The corpus callosum is very small, and has 

 been asserted to be absent. The young Marsupials are born 

 in a very imperfect condition, of very small size, and at a 

 stage when their development has proceeded to a very limited 

 degree only. (In the Kangaroo the period of gestation, is 

 only about thirty-nine days, and in the Didelphidce it is said to 

 be only fifteen or seventeen days). It is believed that there 

 is no placenta or vascular communication between the mother 



* One Kangaroo {Macropus Bruynii) is found in the Indian Archipelago, 

 along with five Phalangers, which differ from the Australian forms in hav- 

 ing the tail partially or entirely naked or scaly. There are also Tree- 

 Kangaroos, and the curious Cuscus, distinguished by a prehensile tail, 

 large eyes, and slow progression. 



