Umbili´cus, n. Navel. Pitted scar, indicating point of entrance of placental vessels into the fœtus. Also, any similar pit or depression, as that on the scape of a feather at junction of rhachis and calamus.

Unarmed Toe. Toe bearing no claw. See Digitus Muticus. (133.)

Un´ciform, a. Hooked.

Under Jaw. See Mandibulum.

Under Parts. See Gastræum.

Under Tail-coverts. (13.) See Crissum.

Under Wing-coverts. (84.) See Tectrices.

Undula´tion, n. Wavy color-marks.

Unguic´ulate, a. Clawed.

Unguis, n.; pl. ungues. Claw.