The intromittent organ, _io_, which projects cephalad from the wall of the cloaca, is here seen as a three-pointed body of considerable size, projecting ventrally from the body. Figure 8 shows in outline the enteron, from the ventral aspect, of an embryo of 20 cm. total length, or at about the time of hatching. The drawing was made from a dissection and, for the sake of simplicity, only the enteron, respiratory organs, heart, and thymus are shown. The jaw is cut through on the left side and is turned over to the right, thus bringing into view the roof of the mouth, _m_, and the dorsal side of the tongue, _tn_. At the same time the pharynx, _ph_, and the wide anterior end of the oesophagus, _oe_, are cut open, exposing the glottis, _gs_, and vocal cords, _vc_. The lungs, _lu_, and trachea, _ta_, which are now fully formed, are dissected loose and drawn over to the right side of the animal, together with the heart, _ht_, and the thymus, _ty_; only one side of the thymus is shown, the other half being hidden by the trachea. The mouth has reached nearly the outline of the adult. The lips are formed and, in the anterior part of the lower jaw, four tooth rudiments, _to_, are externally visible. The mucous membrane of the roof of the mouth, _m_, is covered with rounded papillae, easily seen with a lens but not shown in the figure. The tongue, _tn_, is fully formed, and is free anteriorly and laterally to about the extent that is seen in the adult; the papillae with which it is covered are not so prominent as those seen on the roof of the mouth. At the base of the tongue is the prominent transverse fold, noted in connection with figure 7, that meets above the velum palitinum, not shown here but shown in figure 7. Caudad to these folds is seen the glottis, _gs_, a triangular opening with the vocal cords, _vc_, at its base. The mucosa of the inside of the pharynx and the anterior end of the oesophagus, exposed by the dissection, is thrown into numerous longitudinal folds, not shown in the figure; these well-marked folds extend throughout the length of the oesophagus. The oesophagus, _oe_, tapers gradually from the wide pharynx, _ph_, and then continues as a cylindrical tube of uniform diameter to the right side of the anterior end of the stomach, where it opens into the latter organ. Its walls are thick, and its lumen is almost obliterated by the longitudinal folds of the mucosa, mentioned above.