Note:  Do not rely on this information. It is very old.

Marmoset

Marmoset, any individual of the South American family Hapalidae, the smallest known monkeys, some being only a few inches long. They are also called Squirrel Monkeys from their form, and Ouistitis from their whistling cry. They make affectionate pets, but are very sensitive to cold and need great attention. They have bred in captivity in England.