PO UCHED MAMMALS. 2 1 1 



In most species the pouch is wanting, although it may be represented by two 

 lateral folds of skin, while more rarely it is complete. There are three pairs of 

 pre- molar teeth in each jaw. The females have from five to twenty-five teats. 

 Opossums, which vary in size from that of a cat to that of a mouse, include 

 more than a score of species, all but two of which are restricted to the 

 Neogseic realm, whence the northern forms are probably comparatively 

 recent wanderers. With the exception of the water-opossum, the members 

 of the family are mainly arboreal animals, although some of the smaller kinds 

 are more or less terrestrial. Arboreal species have, however, extended 

 their range to the open Argentine pampas. Whereas the larger kinds 

 are very destructive to poultry, the smaller species subsist exclusively on 

 insects. In those opossums in which the female has no pouch, the young 

 are borne on the back of their parent, generally curling their own tails round 

 that of the latter, which is purposely bent forwards over the back and head. 

 Nearly all the species may be included 

 in the typical genus Didelphys, which 

 may, however, be split up into several 

 sub-generic groups. The first of these 

 is represented solely by the common 

 opossum (D. marsupialis), with its 

 numerous varieties, which is four 

 to five times the dimensions of any 

 other kind, and may be compared, 

 in this respect, to a cat. Its range 

 extends* from the United States to 

 Chili, South Brazil, Uruguay, and 

 Argentina, and it is the only species 

 entering North America above Mexico. 

 As the representative of a sub-genus, p; g . 114 -COMMON OPOSSUM 



it may be characterised as follows : (Dideiphys marsupial-is). 



The very long tail is naked, scaly, and 



highly prehensile ; elongated bristle-like hairs are mingled with the fur ; and 

 the fifth hind toe is much shorter than the fourth, which is of nearly the 

 same length as the first and second. The female has a well-developed pouch 

 for the reception of the young, which at birth are extremely minute. They 

 develop, however, very rapidly, and soon become as large as mice, when 

 they leave the pouch, although returning for the purpose of sucking, or in 

 order to escape from impending danger. Of the habits of this species Mr. 

 C. Lincecum, in the American Naturalist for 1872, writes as follows : 

 "They dwell in hollow logs, stumps, and in holes at the roots of the trees. 

 They do not burrow or prepare dens for themselves, but find such as are 

 ready-made. I have seen them carrying into their holes, at the approach tf 

 cold weather, considerable bundles of dry leaves rolled up in their tail ; they 

 understand the signs of the coming spells of bad weather, and they prepare 

 for it by making for themselves good comfortable beds. They do not 

 hibernate, but are found out hunting in frosty weather. They possess but 

 little caution. Hence they are often found in the poultry-houses, chicken- 

 coops, smoke-houses, and even in our dining-rooms, rustling about for 

 something to eat. I have often seen their tracks in the roads and 

 piths where they had travelled three or four miles to a farmyard, to 

 which they had no doubt been attracted by the crowing of the roosters. 

 They will catch a grown hen and carry her off squalling at the top 



