belonging to the Order Rodentia. . 123 



and though the imperfect nature of the materials at my disposal enables me 

 rather to excite than satisfy the curiosity which naturally attaches to the sub- 

 ject, I may be permitted to indulge a hope that the present notice will at least 

 attract the attention of future inquirers, and be the means of procuring more 

 detailed and accurate information. 



That a vast majority of the terrestrial quadrupeds of Australia belong to 

 the Marsupial family, a group in a great measure peculiar to that locality, 

 and altogether anomalous in relation to the Mammals of other quarters of 

 the globe, is a fact too well known to require further illustration. At the 

 same time, the exceptions to this general rule are much more numerous than 

 has been hitherto suspected : it is true, indeed, that only five, or at most six 

 species of Monadelphine quadrupeds have been hitherto described as indi- 

 genous to that extensive continent ; but the evidence which I shall produce 

 in the present memoir gives us every reason to anticipate an extension of the 

 number, whilst it establishes the singular and hitherto unlooked-for fact, that 

 these exceptions belong exclusively to the Rodent order. Of the five or six 

 monodelphine species already known to share this common habitat with the 

 Marsupial family, one is the Dingo, or native dog, which, as I have observed 

 above, should in all probability be expunged from the catalogue of aboriginal 

 animals ; three belong to the extensive and cosmopolite genus Mas ; and the 

 remaining one, or, perhaps, two species, constitute the genus Hydromys of 

 M. GeofFroy St. Hilaire, the only nonmarsupial form hitherto described as 

 peculiar to Australia. 



Under these circumstances, the announcement of any addition to the indi- 

 genous Rodents of that country becomes in itself a matter of sufficient im- 

 portance ; but the discovery of new forms and genera, either altogether 

 unknown, or hitherto unsuspected to exist in that quarter of the globe, in- 

 vests the subject with more than ordinary interest, and whilst it enlarges the 

 bounds of science, demonstrates the universality of those inscrutable laws 

 which regulate the geographical distribution of animal life. It is, therefore, 

 with feelings of more than common satisfaction that I present this memoir, 

 hoM'^ever necessarily imperfect, to the notice of the Linnean Society; more 

 especially, as it affords me an opportunity of acknowledging my personal 

 obligations to a gentleman to whom science and his country are equally in- 



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