268 



ORDEE VII. 



THE PACHYDERMATA. 



THE Pachydermatous, or thick-skinned order of 

 mammalia, is less uniform in general characters ; 

 and owing perhaps to the generally great size of 

 many species, it appears to have constituted, in a 

 more primordial zoology, a great proportion of the 

 inhabitants of the earth ; for, not only bones of 

 existing forms are abundantly found in the Pliocene 

 and Eocene strata, but numerous genera, totally ex- 

 tinct, and several affording a considerable number of 

 species, have been discovered, all indicating aqua- 

 tical habits, and a residence in localities where fresh 

 water lakes and rivers abounded. Those whose struc- 

 ture necessitates a continual resort in the waters, 

 having more the manners, and even conformation of 

 Manatees, might be placed first in order, but that 

 nearly all have at least similar propensities ; and if 

 the whole structure of the extinct species were known, 

 we would most probably find a series of modifica- 

 tions from the last order passing into the present, of 

 which, for detailed descriptions, we refer to the 

 Fifth Volume of Mammalia of the present work, 

 where the genera and species are described in detail. 



