and deprive those of the others of such a prominence ? Why give 

 one long and the other short anal cerei, or clothe the hind tarsal nails 

 of one with short hairs and leave the other naked? What have 

 those features to do with the differences of structure we have men- 

 tioned in the palm-shaped fore leg, or in the length of the hind leg? 

 These and similar difficulties, arising on every hand, seem to attend 

 every derivative theory of the origin of species. 



