286 Linricean Society. 



are first characterized as follows : Toes long, flexible, and armed with 

 sharp crooked claws ; hind feet provided with a large thumb, without 

 a clan', directed baclcwards, and opposible to the other toes. The Mar- 

 supials of this family, Mr. Ogilby observes, notwithstanding a con- 

 siderable diversity in their organs of mastication, which has led the 

 advocates of the exclusive or predominant influence of the dental 

 system to place the genera they constitute widely apart from each 

 other, are yet united by a chain of affinities so intimate and unbroken, 

 that he cannot hesitate to approximate them thus closely. Hitherto, 

 the Didelphes and Cheironectes have been arranged in the same fa- 

 mily witli the Hylacines, Dasyures, and Perameles, and characterized 

 by the insectivorous form of their dentition ; whilst the Phalangers, 

 Petaurists, and Phascolarcti, liave been distributed throughout diffe- 

 rent groups, under the denominations of Carpophaga, Phyllophaga, 

 Frugivora, &c., all pretending to the rank of natural famihes. 'I'he 

 distinctions derived from the nature of the food, however, agreeably 

 to which the Didelphes have been separated from the Phalangers, 

 and the latter from the Petaurists, Mr. Ogilby affirms to be totally 

 inconsistent with nature ; since, as he has strong reason to believe, 

 from repeated experiments on all the species which have at different 

 times belonged to the collection of the Zoological Society, all these 

 genera are equally omnivorous, and (excepting perhaps certain mi- 

 nute species,) exhibit no predilection for an insectivorous regimen. A 

 more minute examination of the modifications of their different or- 

 ganic systems, confirmed tlie accuracy of the approximation deduci- 

 ble from observations on the nature of their food. The remaikable 

 form, and perfect similarity in all the genera, of their organs of loco- 

 motion, compel them to lead a purely arborial life, for which the 

 great majority of the species are still furtherqualified by their power- 

 ful prehensile tails. Of the five natural genera composing this fa- 

 mily, two only are proper to New Holland, and are common to that 

 country and the islands of the Indian Ocean : the remaining two are 

 peculiar to America, and differ, in some degree, from the Australian 

 genera, both in the conformation of the extremities, and in the num- 

 ber and arrangement of the teeth. These differences, however, are 

 not productive of a corresponding change of function, or of any very 

 marked difference in the habits and oeconomy of the animals. With 

 respect to the analogies of the Scansores with other groups of Mam- 

 mals, it is observed that the Didelphes and Cheironectes are nearly 

 allied to the Cursores of Mr.Ogilby (see Phil. Mag. and Annals, Jan., 

 p. 60.) in their dentition, but in no other respects except those which 

 depend upon the marsupial conformation common to the two families. 

 The alleged analogy between these animals and the Insccticora of Cu- 

 vier is altogether unfounded ; but an affinity may be traced between 

 the Petaurists of the present family, and the Pteromice oi Flying 

 Squirrels among the Rodenlia, and in a slighter degree with the Ga- 

 leopitheci among the Cheiroptera of Cuvier, in the lateral mem- 

 branes with which they are all provided. The Phalangers arc allied 

 to Cheiromys, and the Phascolarcti to the Lcnnircs, and also to the 



Tardiaradi. 



