BIRDS-SUMMARY. 495 



hav8 generally been acquired by the males through variation ana 

 sexual selection, and have been transmitted in various ways ac- 

 cording to the several laws of inheritance — the females and the 

 young being left comparatively but little modified." 



" I am greatly Indebted to the kindness of Mr. Sclater for having 

 looked over these four chapters on birds, and the two following ones 

 on mammals. In this way I have been saved from making mistakes 

 about the names of the species, and from stating anything as a fact 

 which is known to this distinguished naturalist to be erroneous. But 

 of course he is not at all answerable for the accuracy of the state- 

 ments quoted by me from various authorities. 



