Circumduc´tion, n. Movement of a limb by which, if completed, a cone is described.

Cirrh´ous, a. Tufted.

Class, n. Fundamental division of animals: the class of Birds; the class Aves.

Classifica´tion, n. Systematic arrangement.

Clav´icle, n. Collar-bone. In birds, the two clavicles usually unite to form the furculum, merry-thought or wish-bone.

Clavic´ular, a. Pertaining to the clavicles.

Claw, n. (121.)

Claw-joint, n. (122.) See Rhizonychium.

Clit´oris, n. Erectile venereal organ of the female, homologue of the male penis, present in some birds.

Cloa´ca, n. Enlarged lower end of straight gut, receptacle of products of genito-urinary system and refuse of digestion.