196 AFFINITIES AND GEOGRAPHICAL 



The first steps from this aquatic family are perhaps riot to be 

 seen upon earth. It appears as if we had to take up the lines in 

 decidedly inland species the Monke} T s and Sloths, which are 

 sylvan ; the Bats, which are partially aerial ; and man, who is 

 geographically universal. For the sloths alone, do we discern 

 any trace of intermediate species. These appear distinctly 

 enough in the fossil megatherium and megalonyx. ( 81 ) The 

 want of the rest is not a formidable difficulty, for it appears, 

 generally, that the species hovering between sea and land, or 

 those adapted to live upon shores and low grounds, are most 

 apt to become extinct. Hence it is that the tapirine and ele- 

 phantine animals are visibly fading from the face of the 

 earth. Thus has the anoplothere perished, while the llama 

 survives. It cannot fail to be remarked that the geological 

 history of the mammalia is, as far as we obtain from it any 

 distinct ideas, in conformity with these views regarding their 

 classification. The marsupials and aquatics appear early, 

 even before the cretaceous era. After the long blank which 

 that formation represents, what are the animals found predo- 

 minant in the beginning of the tertiary ? The great pachy- 

 derms and cetacea, particularly manatidae. The dog, horse, 

 and other culminating species of the various lines, come com 

 paratively late, the sheep and goat not at all ; man also is ab- 

 sent, till the most recent formations. 



We cannot but regard with profound interest the question 

 respecting our own immediate ancestry. The mind immedi- 

 ately refers to the simial family, whose form, size of brain, 

 and general characters make so manifest an approach to our 

 own. Yet it may be doubted if the particular species whence 

 the human family was derived, has ever come under the at- 

 tention of naturalists. It seems, judging from analogy, as if 

 a larger species than any as yet described were required for 

 this place in the tree of being. It may here be observed that 

 of all the reptilian orders, the batrachian is that which has best 

 pretensions to a place in the origin of the Primates. " It is 

 singular," says Dr. Roget, " that the frog, though so low in 

 the scale of vertebrated animals, should bear a striking resem- 

 blance to the human conformation in its organs of progressive 



