i860.] 



PEDIGREE OF MAMMALIA. 



343 



wolves, jackals, &c. ; yet these have, on our view, descended 

 from a single remote unknown progenitor. With domestic 

 dogs the question is simply whether the whole amount of 

 difference has been produced since man domesticated a single 

 species ; or whether part of the difference arises in the state 



DIAGRAM I. 

 A 



MAMMALS, 

 HOT TRUE MARSUPJALS NOR TRUE PUACEMTAL5. 



DIAGRAM II. 



of nature. Agassiz and Co. think the negro and Caucasian 

 are now distinct species, and it is a mere vain discussion 

 Avhether, when they were rather less distinct, they would, on 

 this standard of specific value, deserve to be called species. 



