216 



MAMMALIA. DIDELPHID.E. 



habits are arboreo-nocturnal, and in common with its 

 rongeners it preys chiefly on insects and small birds. 

 This species is a native of Australia generally, but has 

 not, we believe, been found in Van Diemen's Land. 



THE BANDED MYRMECOBE (Myrmecobius fascia- 

 tus) is an inhabitant of South-western Australia, having 

 been originally discovered and procured by Lieutenant 



Fig 



Dale, at about ninety miles to the south-east of the 

 mouth of the Swan River. The Myrmecobe (fig. 90) 

 is at once distinguished from its insectivorous con- 

 geners, and also from all other marsupials, by the large 

 number of teeth, of which there are fourteen incisors 

 eight above and six below four canines, twelve pre 

 molars, and no less than twenty-four true molars ; in 



90. 



The Banded Mynnecobe (ilyrmecobius fasciatus). 



all, fifty-four. The dental formula thus approaches 

 very closely to that of the extinct and probably mar- 

 supialgenus Thylacotherium. Professor Owen also 

 observes, that it is to a certain extent comparable to 

 the dentition of the armadillos " in the small size of the 

 molar teeth, their separation from each other by slight 

 interspaces, and their implantation in sockets, which 

 are not formed upon a well-developed ridge or process. 

 The molars, however, present a distinct multicuspidate 

 structure, and both the true and false ones possess two 

 separate fangs as in other marsupials." There does 

 not appear to be any necessity to consider this animal 

 as the type of a distinct family. It is about the size of 

 a rat, measuring ten inches from the nose to the root 

 of the tail. The fur exhibits a rufous ground tint 

 generally, the feet being more decidedly red, the back 

 dark brown and banded over the crupper by whitish 

 hairs, similar to those of the thylacine. The head dis- 

 plays a sharply-acuminated muzzle and short pointed 

 ears. The tail is seven inches long and bushy, the 

 anterior feet pentadactylous, and the hind pah- four- 

 toed, all the digits being armed with strong, compressed, 

 curved claws. Its habits are arboreal, and it burrows 

 under the roots of trees in search of insects. 



FAMILY VI. DIDELPHIDJE. 



Under this head are collected together all the Ame- 

 rican marsupials or opossums, properly so called. The 

 species are extremely numerous, for the most part 

 confined to Brazil and the neighbouring provinces of 

 Guyana, Paraguay, and Peru; a few being found in 

 Mexico and California, and one in the United States. 



A single species only occurs in Chili. The opossums 

 are comparatively small, seldom exceeding the size of 

 our domestic cat ; the jaws are furnished with eighteen 

 incisors ten above and eight below four canines, 

 and twenty-eight molars, the anterior twelve being 

 spurious (fig. 91). The head is pointed, the ears large 

 Fir 91. 



Skull of the Virginian Opossum (Didelphis Virginiana). 



and naked, the gape of the mouth very wide, the pro- 

 duced muzzle being furnished with a few long bristles. 

 The tail is prehensile, more or less semi-nude or scaly. 

 The feet are all pentadactylous, but the pollex of the 

 hinder pair is opposable to the other digits, and clawless. 

 The opossums are arboreal and nocturnal in their habits, 

 preying chiefly upon birds, eggs, insects, and even fruit. 

 Their movements, however, are rather sluggish than 

 otherwise, and their presence is recognizable by the 

 peculiar fetid odour of their skin. They have a simple 

 stomach and moderately capacious ccecum. 



THE VIRGINIAN OPOSSUM (Didelphis Virginiana). 

 or COMMON POSSUM Plate 30, fig. 96 enjoys the 

 distinction of being the first known to naturalists. It 



