242 ANATOMY OF THE RABBIT 



10. Sympathetic plexuses. In the descending mesocolon will be 

 found the inferior mesenteric ganglion (g. mesentericum in- 

 ferius) , a narrow curved body situated in front of the inferior 

 mesenteric artery. Surrounding the abdominal aorta and 

 appearing in the mesocolon is the abdominal aortic plexus 

 (plexus aorticus abdominalis). It is connected anteriorly with 

 the coeliac and superior mesenteric plexuses (p. 213) accom- 

 panying the corresponding vessels, and with the renal plexuses 

 accompanying the renal vessels to the kidneys; posteriorly with 

 the inferior mesenteric and spermatic plexuses about the 

 inferior mesenteric and internal spermatic arteries, and with 

 the hypogastric plexus about the pelvic vessels. 



11. By division of the rectum close in front of the pelvis and of the 

 peritoneal attachments, the intestines may be separated and 

 laid out in an extended condition. The relations to one another 

 of the ileum, caecum, and colon are studied thus to much 

 better advantage than in the natural position. The caecum 

 should be opened lengthwise and the spiral valve examined 

 (Fig. 55). 



12. The lymphatic system can be studied adequately only in specially injected 

 specimens, though the larger mesenterial lymph glands have been pointed 

 out in the foregoing directions. The lymphatics from the liver and intestines 

 converge in lymph nodes, of which there are usually two near the posterior 

 end of the mesoduodenum, two associated with the portal vein near the lesser 

 curvature of the stomach, and two near the junction of the splenic and 

 superior mesenteric veins. These are all connected with the large mass of 

 lymph nodes near the origin of the superior mesenteric artery, whence an 

 intestinal trunk empties into one of the lumbar trunks, which run in the 

 lateral walls of the abdominal aorta. 



VI. THE URINOGENITAL SYSTEM 



For the general relations of the urinogenital organs, see p. 122. 



(A). The Urinary Organs 



The central organs of excretion, the kidneys (renes), occupy an 

 anterior position on the dorsal wall of the abdomen. The right 

 kidney is placed a little farther forward than the left and is largely 

 covered by the right posterior lobule of the liver. In addition to a 



