DIDELPHID.E. MAMMALIA. DIDELPHID.K. 



217 



is widely distributed throughout the United States, and 

 is especially abundant towards the south. A full-grown 

 specimen measures twenty inches in length, exclusive of 

 the tail, for which other fourteen inches must be allowed. 

 The fur has a dusky-brown colour, the individual 

 hairs being whitish, with brown tips. The legs are 

 nearly black, the digits being lighter coloured or whitish. 

 The head is fulvous-white, with a dusky suffusion round 

 the eye ; the ears are black, with a yellow patch at the 

 upper border ; the root of the tail is also dark coloured. 

 The Possum is very destructive to poultry, and proves 

 a troublesome pest. The female produces sometimes 

 as many as sixteen young at a birth, which, when at 

 first transferred to the marsupial pouch, are extremely 

 minute. The eyes of the young open about the fiftieth 

 day, when the cubs are as large as ordinary mice. 

 The flesh is said to be good eating. 



Among the more interesting or noticeable of the 

 other species, we may mention the following: The 

 TEXAS POSSUM (Didelphis Californica). which is dis- 

 tinguished by its smaller size, its less rounded and 

 more pointed ears ; the hairy or basal portion of the 

 tail being also shorter. According to Mr. J. H. Clarke 

 of the United States expedition, this species is parti- 

 cularly fond of the black persimmon, an abundant fruit 



on the borders of the Rio Grande. The D. Murina 

 is found in Mexico, Guyana, Peru, and Brazil ; the D. 

 dorsigera in Surinam. " These species," as Van der 

 Hoeven observes, " carry their young on the back when 

 they are sufficiently developed to leave the teat, to 

 which at first they were attached, whilst they throw 

 their tails like tendrils round the caudal appendage of 

 their parent." In both the tail is fully as long as the 

 body, and the ears are largely developed. AZARA'S 

 POSSUM (D. AzarcR) pretty closely resembles the Texas 

 form. According to Mr. Spencer F. Baird, it is distin- 

 guished by its white head and neck, with a central dark 

 stripe along the forehead to the dusky part of the nape. 

 The ears and toes are flesh-coloured. The CRAB- 

 EATING OPOSSUM (D. cancrivora)so called from its 

 propensity for eating these Crustacea is a large spe- 

 cies, possessing no well-defined markings on the head ; 

 the generically distinctive, long, and sparsely scattered 

 hairs of the short fur existing more or less abundantly 

 in all the opossums. The fur exhibits a deep black 

 colour. 



THE YAPOCK (Cheironectes variegalus), or PETITE 

 LOUTRE of Biiffon, is an aquatic form of opossum 

 inhabiting the river banks of Brazil and Guyana (fig. 

 92). The only point in which it appears to differ 



The Yapock ^lieironectes variegatus) 



materially from the ordinary opossums, has reference 

 to the palmated character of the feet, which are 

 supplied with interdigital membranes. In all other 

 particulars it conforms to the genus Didelphis. The 



Yapock is little more than a foot in length, exclusive 

 of the tail, which is scaly and prehensile, and nearly 

 as long as the body. It is an expert swimmer, and 

 feeds upon fishes, Crustacea, and other aquatic animals. 



OEDER XIV. MOXOTREMATA. 



IT is not a little significant of the universality of plan 

 pervading all vertebrate formations, that we should 

 find on examining the skeleton and viscera of the 

 monotremes, a decided approximation to certain of 

 VOL. I 



the distinguishing characteristics of birds and reptiles. 

 At first sight there is little to suggest this relationship, 

 except in so far as the bill-like jaws of Ornithorynchus 

 are admitted to resemble a duck's beak ; but on closer 



2E 



