The noise consists in a short, but not rough, nasal grunt, which is monotonously repeated about four times in quick succession (3/6.

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.): the name Tucutuco is given in imitation of the sound.

Where this animal is abundant, it may be heard at all times of the day, and sometimes directly beneath one's feet.

When kept in a room, the tucutucos move both slowly and clumsily, which appears owing to the outward action of their hind legs; and they are quite incapable, from the socket of the thigh-bone not having a certain ligament, of jumping even the smallest vertical height.