THE LYMPHATIC SYSTEM. 333 
system is present in the cat, it is much less easily demonstrated 
than the superficial system. , 
4. Lymphatics of the Thorax and Abdomen.—In the 
thorax are a number of lymphatic glands which are apparently 
not constant in number and position. One is commonly found 
dorsad of the bifurcation of the superior vena cava, one ventrad 
of the mammary vein, several small ones about the bifurcation 
of the trachea, one or more in the region of the aortic arch, 
and a number of small ones scattered in the mediastinum. 
The vessels from these glands finally join either the right lym- 
phatic duct or the thoracic duct; the details have not been 
worked out and are probably variable. 
In the abdominal cavity a number of mesenteric glands, of 
considerable size, are found in the mesentery and in the meso- 
colon. Inthe mesocolon these are usually separate, forming 
a chain of glands following the colon about one and a half 
centimeters from it. In the mesentery the glands are mostly 
united into a very large one, formerly known as the pancreas 
aselli; this is the largest lymph-gland in the body. It is a 
curved structure, four or five centimeters in length, lying in 
the central region of the mesentery. 
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 lym- 
phatics 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 con- 
tinuation of the receptaculum chyli. It lies on the dorsal side 
