INTRODUCTION. 91 



Baron Cuvier classed the quadnimana, then carni- 

 vora, rodentia, edentata, marsupialia, pachydermata, 

 ruminantia, and cetacea. This arrangement is open 

 to the objection, that the singular form of winged 

 quadrupeds, with very varying dentitions, and with 

 some important organs in their structure, assimila- 

 ting them to quadrumana ; and again, others, des- 

 tined to live without, or with little vision, and with 

 organisations very distinct, both being chiefly insec- 

 tivorous, should be grouped with carnivora, strictly 

 so called. Next we find the marsupialia placed in 

 the centre of the series ; an order in itself peremp- 

 torily demanding sub-division into two ; the first of 

 them, even there, comprehending animals, by their 

 dentition and diet, corresponding to carnivora, ro- 

 dentia, and edentata, but all assimilated by the still 

 more important condition of the phenomena of their 

 progeniture, and the construction in the females of 

 a pouch, to bear their immature offspring. In short, 

 the marsupialia and monotremata differ from all 

 other mammals, by being ovo-vivaporous or impla- 

 cental. For these reasons, in the time of Cuvier, 

 not as yet fully ascertained, Monsieur de Blainville, 

 and after him the Prince of Canino, pointed out the 

 propriety of modifying this part of the mammalian 

 system ; but Mr. Waterhouse first formed the pre- 

 sent arrangement, and Professor Owen first com- 

 pletely demonstrated the necessity of removing the 

 whole to a second series, independent of the pla- 

 centaL He perceived the necessity of adding to the 

 general considerations, applicable to the classification 



