341 



it i. obriout that these differences of dnttition are unimportant, and afford no jut grounds for 



M!MWTU> r4 ' t ' n**wM* 



The Phalangers, being provided with hinder hand* and prehensile tails, are strictly arboreal 

 animals, and hare a ckwe external reamiblanre to toe Opossums, by which namr they are 

 gwerally known in Australia and the islands of the Indian Archipelago, where alone they 

 hare hitherto been found. They differ from the Opossums chiefly in their dentition ; and 

 in accordance with this difference their diet is more decidedly of a vegetable kind. The 

 Australian Phalangers feed chiefly on the tender buds and the leave* of Eucalypti ; but accord- 

 ing to Temminck, the Indian Phalangers are omnivorous, and combine insects with fruiu and 

 leaves. 



Pretexted by Ronald GMHH, Jvuf. 



Tribe EKTOMOPHAGA. 



Genus Didelpkit. 



1867. The skeleton of the Virginian Opossum (Diddjihit llrginiana). 



The median crest of thr cranium is developed from the frontal, parietal and niperoccipital 

 bones, and is of unusual height : the transverse superoccipital crest is also strongly developed. 

 The second to the fifth cervical vertebra are remarkable for the large site of their spinous 

 processes, which form a thick four-sided mass of bone. The inner condyle of the humerus 

 is perforated. The marsupial bones are strongly developed : an ossified patella is preserved 

 in the right leg. The transverse processes of sis cervical* are perforated ; those of the seventh 

 are notched. 13 vertebra- are dorsal, 6 lumbar, I sacral, and 17 caudal, of which hut the 

 third to the eleventh inclusive bear bjeniapophyses. 



MM*. lirookn. 



1868. The skull of a Virginian Opossum (Didelphi* Firyiniamd), prepared to cxlnlut 

 the teeth. 



The dental formula of the genus QiMpAu is: i tri, e {={, p ^, m 50. The 

 Opossums resemble, in their dentition, the Bandicoots more than the Dasyures ; but they 

 closely resemble the latter in the tuberculous structure of the molars. The two middle 

 incisors of the upper jaw are more produced than the others, from which they are also 

 separated by a short interspace. The canines are well developed ; the upper being alway* 

 stronger than the lower. The false molars are simply conical, but are more compressed than 

 in the carnivorous Marsupial*. The posterior false molar is the largest in the upper jaw : 

 the middle one is the largest in the lower jaw : the anterior one is the smallest in both jaws. 

 The true molar* are beset with sharp cusps, which wear down into tubercles as the animal 

 advances in age. The crowns of the upper molars present a triangular horaontal section : 

 the base of the triangle is turned forward in the posterior molar ; and obliquely inwards and 

 outward* in the rest. In the lower jaw the true molars an narrower aad of more equal sue 



