The arytenoid cartilages forming the ends of the ary-epiglottic folds are movable, approaching and separating alternately during the act of respiration, while during phonation they are pressed against each other, thus obliterating the space between them which is seen when they are separated. This space is the inter-arytenoid space or commissure, and is formed by the lateral walls of the arytenoid cartilages and the upper margin of the posterior portion of the cricoid cartilage. The mucous membrane in this commissure is very loosely attached to the deeper structures, and is thrown into folds by the approximation of the arytenoid cartilages. Its color is much lighter than that of the ary-epiglottic folds, due to the shining through of the cricoid cartilage. Outside of the ary-epiglottic folds and the inter-arytenoid commissure is the tissue forming the posterior and lateral walls of the oesophagus (not shown in the diagrams), and near the epiglottis a space called the pyriform sinus is noticed between the ary-epiglottic folds and the wall of the oesophagus. Running from the epiglottis to the ary-epiglottic folds are two broad bands, one on either side, covered with mucous membrane and of a pinkish-red color, which are lost on either side in the tissue forming the walls of the laryngeal cavity, while toward the middle of the image they present concave and tolerably sharp edges. These are the ventricular bands, which were formerly termed the false vocal cords, and which form the lip to the opening of the ventricle of the larynx. Between the ventricular bands filling up the central portion of the image are seen the vocal cords, two bands of a pearl-white color which are attached to a cartilaginous process of the arytenoid cartilages, and run from these parallel with each other to the angle of the thyroid cartilage immediately below the tubercle of the epiglottis. These present sharp edges toward each other, and follow the motions of the arytenoid cartilages to which they are attached, so that when in inspiration the cartilages are separated the edges of the vocal cords are also some distance apart, forming, together with the inter-arytenoid commissure, a triangular opening called the glottis. That portion of the opening which is bounded on either side by the edges of the vocal cords alone is called the membranous portion, while the base of the triangle is termed the cartilaginous portion, being bounded on either side by the vocal processes of the arytenoid cartilages. This portion is readily distinguished from the membranous portion by its slightly yellow color, and by the fact that a very obtuse angle is formed at the junction of the two portions when the glottis is wide open during respiration. Through the open glottis the lower edge of the cricoid cartilage and several of the rings of the trachea can usually be seen, and there are a few cases in which even the bifurcation of the trachea can be dimly illuminated, showing in the