280 



DIDELPHUS. 



white, the black hairs being shorter than the yellowish, 

 and the white ones longer, but with a portion of black 

 at the points. These long hairs form a sort of line 

 along the back, and when the animal is excited, it has 

 the power of erecting them. The legs and feet are 

 wholly black, with the exception of the last joint and 

 the claws, which are white ; the tail, which is covered 

 with scales and very short hair, is black at the base, 

 and white for more than two-thirds of its length 

 toward the tip. It is tapering to the end, and 

 prehensile. 



Crab-eating opossum 



This animal is remarkably low upon the legs. Its 

 whole length is about thirteen inches, exclusive of 

 the tail, and its height not above six inches, while, 

 from its applying the whole length of the hind feet to 

 the ground, and having the fore ones short and 

 crooked, it is much lower at the shoulders and the 

 crupper than at the middle of the back. It has been 

 observed principally on the warm shores of South 

 America, where it resides in the holes of the rocks 

 above water, and seeks its food chiefly off crabs and 

 other crustaceous animals. Its hind feet are well 

 adapted for grasping, like hands, and its fore paws, 

 which have sharpened crooked claws, and the toes 

 much divided, are also good prehensile instruments ; 

 but, in addition to these, it is said to render its tail 

 available, by thrusting it into the holes which the 

 crabs inhabit, and drawing them forth to their 

 destruction. 



The FOUR-EYED OPOSSUM Didelphns Opossum, 

 is the only other known species which has the 

 nmrsupium fully developed. Like the former, it is an 

 inhabitant of the warmer shores of South America, 

 but it is a more inland animal, and its food is different. 

 It is rather smaller than either of the former, being 

 about a foot in length, with the tail about one foot 

 two inches. Its head is pointed, the whole of the 

 profile forming a straight line. The ears are large, 

 round in their form, and very thin in their substance. 



The prevailing colour in the upper part is reddish 

 brown, mixed with grey on the back, but purer on the 

 head. On this dark colour there are placed two 

 circular spots of white in front of the ears, and it it 

 from these two spots that the animal gets the name of 

 four-eyed, just as some breeds of dogs in this country 

 get the same appellation from two brown spots on a 

 black ground immediately over the eyes. The under 

 part is dull white ; a small portion at the root of the 

 tail is covered with the same hair as the upper part 

 of the animal, while the remaining part of that organ 

 is nearly naked and scaly. The female has six or 

 seven teats in the pouch, and in these animals there is 

 a different arrangement from the teats of common 

 mammalia ; in them they are arranged in pairs right 

 and left, while in these marsupial animals there is one 

 central, and the others surrounding. 



The Opossumt which have no pouch inclosing and 

 concealing the teats, are smaller than those in which 

 the females are furnished with that appendage ; but, 

 though the teats are exposed, the young are placed 

 upon them, and adhere and grow there in a manner 

 not very different from those which are enclosed in 

 the pouch ; and the abdomen is supported by 

 marsupial bones in a similar manner. This circum- 

 stance shows that the pouch, that is, the external 

 duplicature of the pouch, is not the essential part, but 

 merely a protecting membrane ; for it does not 

 appear that the species that are without it carry their 

 young with more difficulty than the others. 



The MEXICAN OPOSSUM, or CAYOPOHN Didelphui 

 dorsigera. This species is about seven inches and a 

 quarter in length ; the eyes and surrounding spaces are 

 brown, there is a line of the same colour up the middle 

 of the face, and the sides of the head are brownish 

 ash. All the upper part of the body is greyish yel- 

 low, and the under side yellowish ; the ears are 

 surrounded with yellow at the base, and the tail is 

 spotted with brown and yellow, having a part near 

 the insertion covered with hair, and the remainder 

 naked and scaly. This is the species which is described 

 under the name of the slender -tailed opossum by some 

 naturalists. 



The MARMOT OPOSSUM Didelphus murina. This 

 species is less than the larger of European rats. 

 It is the marine opossum of Pennant and Shaw ; and 

 though smaller in size, it does not differ greatly in its 

 general appearance from the species just mentioned. 

 The muzzle is rather more pointed, the ears rounder, 

 and the head more convex ; the eyes are situated in 

 the middle of a transverse band of black, which is 

 broader above than under their openings, and does 

 not extend far beyond their openings laterally. 

 The upper part of the body is a mixture of fawn and 

 ash colour, the under part is whitish, but with a mix- 

 ture of fawn which is gradually less and less con- 

 spicuous as it approaches the central part of the 

 abdomen. These little animals are, however, subject 

 to very considerable variations in the colour of their 

 attire ; and they have, on this account, sometimes 

 been described under different names. The females 

 are furnished with about fifteen teats, situated among 

 the folds of skin in the groins ; and the young ones, 

 after they are discharged from the uterus, adhere firmly 

 to these, like little round buttons, until they acquire 

 the developed form of organised animals. The power 

 of adhering to the mother is very wonderful in all the 

 marsupial animals, but more especially in those which 

 are not provided with a developed pouch ; and after 

 they have acquired some form, and are detached from 



