Cra´ni-al (L. cra´nium, the skull). Pertaining to the skull. The nerves which arise from the brain are called cranial nerves.

Cri´coid (Gr. κρίκος, kri´kos, a ring). A cartilage of the larynx, resembling a seal-ring in shape.

Crys´tal-line Lens (L. crystal´lum, a crystal). One of the so-called humors of the eye; a double convex body situated in the front part of the eyeball.

Cu´ti-cle (L. dim. of cu´tis, the skin). The scarf-skin; also called the epider´mis.

Cu´tis (Gr. σκῦτος, skutos, a skin or hide). The true skin, lying beneath the cuticle; also called the der´ma.

De-cus-sa´tion (L. decus´sis, the Roman numeral ten, X). A reciprocal crossing of fibres from side to side.

Di´a-phragm (Gr. διαφράσσω, diaphrasso, to divide by a partition). A large, thin muscle which separates the cavity of the chest from the abdomen; a muscle of respiration.

Dif-fus´ion of Gases. The power of gases to become intimately mingled, without reference to the force of gravity.

Duct (L. du´co, to lead). A narrow tube; the thoracic duct is the main trunk of the absorbent vessels.

Du-o-de´num (L. duode´ni, twelve). The first division of the small intestines, about twelve fingers-breadth long.