108 CHARLES DARWIN 



It is rather curious to find how incapable these birds must 

 be of acquiring any notion of thickness, for although they 

 were constantly flitting over the low wall, they continued 

 vainly to bore through it, thinking it an excellent bank for 

 their nests. I do not doubt that each bird, as often as it 

 came to daylight on the opposite side, was greatly surprised 

 at the marvellous fact. 



I have already mentioned nearly all the mammalia com- 

 mon in this country. Of armadilloes three species occur, 

 namely, the Dasypus minutus or pichy, the D. villosus or 

 peludo, and the apar. The first extends ten degrees further 

 south than any other kind ; a fourth species, the Mulita, 

 does not come as far south as Bahia Blanca. The four spe- 

 cies have nearly similar habits ; the peludo, however, is noc- 

 turnal, while the others wander by day over the open plains, 

 feeding on beetles, larvae, roots, and even small snakes. The 

 apar, commonly called mataco, is remarkable by having only 

 three moveable bands; the rest of its tesselated covering 

 being nearly inflexible. It has the power of rolling itself 

 into a perfect sphere, like one kind of English woodlouse. 

 In this state it is safe from the attack of dogs; for the dog 

 not being able to take the whole in its mouth, tries to bite 

 one side, and the ball slips away. The smooth hard cover- 

 ing of the mataco offers a better defence than the sharp 

 spines of the hedgehog. The pichy prefers a very dry soil; 

 and the sand-dunes near the coast, where for many months 

 it can never taste water, is its favourite resort: it often tries 

 to escape notice, by squatting close to the ground. In the 

 course of a day's ride, near Bahia Blanca, several were gen- 

 erally met with. The instant one was perceived, it was 

 necessary, in order to catch it, almost to tumble off one's 

 horse; for in soft soil the animal burrowed so quickly, that 

 its hinder quarters would almost disappear before one could 

 alight. It seems almost a pity to kill such nice little ani- 

 mals, for as a Gaucho said, while sharpening his knife on 

 the back of one, "Son tan mansos" (they are so quiet). 



Of reptiles there are many kinds: one snake (a Trigono- 

 cephalus, or Cophias 18 ), from the size of the poison channel 

 in its fangs, must be very deadly. Cuvier, in opposition to 



13 M. Bibron calls it T. crepitans. 



