96 BAHIA BLANCA. [CHAP v. 
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 species have nearly similar 
habits; the peludo, however, is nocturnal, while the others 
wander by day over the open plains, feeding on beetles, larvee, 
roots, and even small snakes. The apar, commonly called ma- 
taco, 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 
covering 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 generally 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 animals, 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), from the size of the poison channel in its 
fangs, must be very deadly. Cuvier, in opposition to some other 
naturalists, makes this a sub-genus of the rattlesnake, and inter- 
mediate between it and the viper. In confirmation of this opi- 
nion, I observed a fact, which appears to me very curious and 
instructive, as showing how every character, even though it may 
he in some degree independent of structure, has a tendency to 
vary by slow degrees. The extremity of the tail of this snake 
is terminated by a point, which is very slightly enlarged; and 
as the animal glides along, it constantly vibrates the last inch; 
and this part striking against the dry grass and brushwood, pro- 
duces a rattling noise, which can be distinctly heard at the dis- 
