70 The Naturalist in La Plata. 



diminish or increase ; the old go, and others with 

 different weapons and a new strategy take their 

 place ; and just as a skilful man " fighting the 

 wilderness " fashions a plough from a hunting- 

 knife, turns his implements into weapons of war, 

 and for everything he possesses discovers a use 

 never contemplated by its maker, so does Nature 

 only with an ingenuity exceeding that of man 

 use the means she has to meet all contingencies, 

 and enable her creatures, seemingly so ill-provided, 

 to maintain their fight for life. Natural selection, 

 like an angry man, can make a weapon of any- 

 thing ; and, using the word in this wide sense, the 

 mucous secretions the huanaco discharges into the 

 face of an adversary, and the pestilential drops 

 " distilled " by the skunk, are weapons, and may be 

 as effectual in defensive warfare as spines, fangs 

 and tushes. 



I do not know of a more striking instance in the 

 animal kingdom of adaptation of structure to 

 habit than is afforded by the hairy armadillo 

 Dasypus villosus. He appears to us, roughly 

 speaking, to resemble an ant-eater saddled with a 

 dish cover ; yet this creature, with the . cunning 

 which Nature has given it to supplement all de- 

 ficiencies, has discovered in its bony encumbrance a 

 highly efficient weapon of offence. Most other 

 edentates are diurnal and almost exclusively insec- 

 tivorous, some feeding only on ants ; they have 

 unchangeable habits, very limited intelligence, and 

 vanish before civilization. The hairy armadillo 

 alone has struck out a line for itself. Like its fast 

 disappearing congeners, it is an insect-eater still, 



