synotus

from The Century Dictionary.

• noun (Keyserling, 1840.) A genus of long-eared bats, of the family Vespertilionidæ and subfamily Plecotinæ, having the rim of the ear produced in front of the eye, the incisors four above and six below, the premolars two on each side of each jaw. The type is the barbastel of Europe, S. barbastellus. Another species is S. darjelingensis.
• noun [lowercase] A double monster having the body united above a common umbilicus, the head being incompletely double, with a face on one side and one or two ears on the other.