Into the mesenteric glands pass lymphatic vessels from the viscera of the abdomen. From the mesenteric glands one or two large lymphatic vessels pass craniodorsad, at first with the portal vein, then dorsad of it. This vessel reaches the dorsal side of the aorta near the cranial end of the kidney, where it enters a large fusiform vessel, the =receptaculum chyli=, which stretches from the cranial end of the kidney craniad between the crura of the diaphragm into the thorax. The receptaculum receives other lymphatics from the various organs of the abdominal cavity as well as vessels coming from the pelvic region, and from the =iliac= glands. These lie beside the iliac artery, receive lymphatics from the hind limbs, and send lymphatics craniad to the receptaculum chyli. The latter forms the beginning of the =thoracic duct=. The thoracic duct (Fig. 118, 5, page 282) enters the thoracic cavity between the crura of the diaphragm as a continuation of the receptaculum chyli. It lies on the dorsal side of the aorta (_a_), somewhat to the left. It passes along the aorta, gradually coming to lie more on its left side, and finally leaves that vessel near the aortic arch. The duct continues thence straight craniad along the left side of the œsophagus till it reaches the external jugular vein at its junction with the subclavian. In this region the thoracic duct usually unites with the lymphatics coming from the head and arm, then enters the external jugular vein, or the innominate at the point of union of external jugular and subclavian. In its passage through the thorax the duct frequently divides into two or three divisions which pass along parallel to each other for a distance, then reunite. Such division into two or three parts is especially frequent just before the union with the jugular vein. The numerous valves in the thoracic duct give it a beaded appearance. 5. =Lymphatics of the Pelvic Limbs.=--A number of lymphatic vessels are formed on the dorsum and the sole of the foot. These pass to the lateral side, forming a network on the lateral and dorsal surface of the ankle-joint, and finally unite into two main trunks which accompany the vena saphena parva. In the popliteal space these enter the =popliteal gland= which lies imbedded in the fat of that region. From the popliteal gland one or two trunks accompany the superficial division of the vena saphena parva across the lateral surface of the biceps muscle, and finally thus reach the pelvic cavity. Here they join the lymphatics of the pelvic region, which all pour their lymph at last into the thoracic duct. Inguinal glands are either very small or not present in the cat. The pelvic limbs have perhaps a deep system of lymphatics, accompanying the deep veins; if so, they are not easily demonstrable. [Illustration: FIG. 133.--CRANIAL PORTION OF THE SPINAL CORD, WITH THE CERVICAL ENLARGEMENT. DORSAL VIEW.