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, 
