marmoset

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various small clawed monkeys of the genera Callithrix and Cebuella, found in tropical forests of the Americas and having soft dense fur, tufted ears, and long tails.

Century Dictionary and Cyclopedia

1. n. A little ape or monkey.
2. n. Now, specifically, a small squirrel-like South American monkey of the family Hapalidæ, or Mididæ (which see for technical characters). There are numerous species, referred to two leading genera, Hapale and Midas, and known by many names, as squirrel-monkeys, oustitis, tamarins, etc. They are the smallest of the monkey tribe, ranging from a few inches to a foot in length, with a long, bushy, non-prehensile tail, and thick, soft, silky or woolly fur, in some species lengthened into conspicuous ear-tufts or a kind of mane. The coloration is extremely variable. The thumb of the hand is not opposable, but the inner toe of the hind foot serves as a thumb, and has a flat nail, all the other digits of both extremities being armed with sharp claws of great service in climbing. Marmosets are confined to tropical America, having their center of abundance in northern South America; they live in the woods, and feed chiefly upon insects. They are extremely sensitive to cold, but with proper care may be kept in confinement, and make amusing pets, though their intelligence is low. Characteristic examples are the common black-eared marmoset, Hapale jacchus, and the marakina or tamarin, Midas rosalia. See cut under Hapale.
3. n. An ugly little fellow; a conceited “puppy.”

Wiktionary

1. n. A small Central and South American monkey (genus Callithrix), with claws instead of nails, and a rather primitive layout.

GNU Webster's 1913

1. n. Any one of numerous species of small South American monkeys of the genera Hapale and Midas, family Hapalidæ. They have long soft fur, and a hairy, nonprehensile tail. They are often kept as pets. Called also squirrel monkey.

WordNet 3.0

1. n. small soft-furred South American and Central American monkey with claws instead of nails