_Insertion_ into the median dorsal raphe of the pharynx. The dorsal fibres are inserted into the base of the sphenoid. The ventral fibres pass lengthwise of the pharynx, closely connected with those of the stylopharyngeus (Fig. 96, _l_), and finally reach the level of the larynx. _Action._--Constrictor of the pharynx. 3. =The Œsophagus.=--The œsophagus is a straight tube, dorsoventrally flat when empty, which extends from the pharynx to the stomach. It has a uniform diameter when moderately dilated of about one centimeter. It lies dorsad of the trachea and against the longus colli muscles (Fig. 72, _g′_) covering the centra of the cervical vertebræ, until it reaches the caudal end of the thyroid gland (Fig. 96, 6); then it passes to the left and lies laterodorsad of the trachea until it reaches the bifurcation of the trachea. It there returns to the median line, passes gradually distad, separated from the vertebræ by the aorta, and finally pierces the diaphragm about two centimeters from the dorsal body wall, and enters the stomach. Its attachment to the diaphragm is loose enough to permit of longitudinal motion. In passing through the thoracic cavity it lies in the posterior mediastinum ventrad of the aorta. Its wall consists of a muscular coat, a submucosa, and a mucosa, and its inner surface presents many longitudinal folds. It has no serous covering, its side walls being merely in contact with the halves of the mediastinal septum. 4. =The Stomach. Ventriculus= (Fig. 97).--The stomach is the widest part of the alimentary canal. It is a pear-shaped sac, the long axis of which is curved nearly into a semicircle. The broad end of the sac lies to the left and dorsad; here the stomach communicates with the œsophagus (_a_). The narrowed end extends to the right and lies more ventrad than the other end; it passes here into the duodenum (_g_). That portion of the stomach which communicates with the œsophagus is known as the =cardiac= end (_b_); the opposite is the =pyloric= end. Owing to the curved form of the stomach above mentioned it is possible to distinguish a concave and a convex side. The concave side is directed craniad and dextrad; it is called the =lesser curvature= of the stomach (_c_). The longer convex border is directed caudad and to the left; it is called the =greater curvature= (_d_). The greater curvature extends to the left, next to the œsophagus, into a prominent convexity known as the fundus (_e_) of the stomach.