Mr. Owen
informs me that a part of the oesophagus is so constructed
that nothing much larger than a crowquill can be passed down.
Certainly the broad teeth and strong jaws of this animal are
well fitted to grind into pulp the aquatic plants on which it
feeds.
[6] At the R. Negro, in Northern Patagonia, there is an animal
of the same habits, and probably a closely allied species, but
which I never saw. Its noise is different from that of the
Maldonado kind; it is repeated only twice instead of three or
four times, and is more distinct and sonorous; when heard from
a distance it so closely resembles the sound made in cutting
down a small tree with an axe, that I have sometimes remained
in doubt concerning it.
[7] Philosoph. Zoolog., tom. i. p. 242.
[8] Magazine of Zoology and Botany, vol. i. p. 217.
[9] Read before the Academy of Sciences in Paris. L'Institut,
1834, p. 418.
[10] Geolog. Transact. vol. ii. p. 528. In the Philosoph.
Transact. (1790, p. 294) Dr. Priestly has described some
imperfect siliceous tubes and a melted pebble of quartz,
found in digging into the ground, under a tree, where a man
had been killed by lightning.
