considered as a zoological Character. 5 '21 



intermixed where these climes begin to lose their essential ana 

 distinguishing character, and gradually merge into one another. 

 Now, this is precisely the case with respect to the Indian isles : 

 they are neither entirely Asiatic nor entirely Australian, but 

 a kind of debatable land, or, rather, neutral ground, in which 

 the productions of both continents meet and mingle; the 

 Asiatic Apes and Macacs, in the present instance, sharing the 

 same habitat as the naked-tailed Phalangers, the represent- 

 atives of the didelphidous Pedimana of New Holland and 

 South America. The exception to the general law of habitat 

 is, consequently, more apparent than real ; and I am therefore 

 justified in insisting upon this beautiful and remarkable prin- 

 ciple in the physical geography of animals, that there are no 

 quadrumanous forms in the New World, and no pedimanous 

 in the Old. I have always shown, in tracing the other affini- 

 ties which exist between the constituent members of the 

 Quadrumana and Pedimana respectively, that the prehensile 

 power of the tail is appropriate only to the latter family, and 

 absolutely unknown in the former. It follows, as a corollary 

 from this principle and the law of habitat just established, that 

 there should be no prehensile-tailed animals in the Old World ; 

 and this curious fact is equally true, since the only quadrupeds 

 with prehensile tails which do not belong to the Pedimana (the 

 Synetheres, Myrmecophaga, and Cercoleptes) are equally 

 confined to South America. 



It has been already observed, in the fourth place, that, as 

 the Simiadae among the Pedimana form a parallel group to 

 the Simise among the Quadrumana, so also the Didelphidae 

 in the former family may be considered as representing the 

 Lemuridae in the latter. This relation, however, is neither so 

 obvious nor so important as many of those which I have 

 already developed. It is displayed, principally, in the greater 

 prolongation of the face and the lengthened muzzle, which 

 equally characterise the Lemuridae and Didelphidae, as com- 

 pared with the Simiae and Simiadae, respectively ; in the pro- 

 cumbent position and abnormal characters of the incisor teeth, 

 both as regards the number and the form of these organs ; and 

 generally in the more limited faculties, as well intellectual as 

 physical, of both these groups. It is unnecessary, however, 

 to insist farther upon relations which are obvious to the most 

 casual observer, and which are otherwise of very small im- 

 portance in a zoological point of view. 



I have hitherto spoken of the Pedimana as composed of 

 two natural families only, the Simiadae and the Didelphidae; 

 but there is, in reality, a third and very singular form included 

 Vol. I. — No. 10. n. s. q q 



