MAMMALIA. 175 



and fleshy. Each semilunar ganglion assists in forming plexuses, consisting of 

 branches connected together in some instances by a very delicate or dense membrane, 

 or a more fleshy substance, and are more or less extensive according to the magnitude 

 or length of corresponding portions of the viscera, but the general disposition of the 

 whole is very similar to that in man. Some branches pass on the arteries of all the 

 stomachs of ruminating animals, as they do on those of the single one in others. The 

 hepatic, splenic, renal and spermatic plexuses, are very similar to those in man, but 

 generally not quite so intricate, and there are similar connexions with branches of 

 each trunk of the par vagum. When the duodenum is longer, more branches pass 

 from the superior mesenteric plexus with the branch of this artery, to meet those 

 proceeding from the hepatic plexus on a branch of the right inferior gastric artery ; 

 in the jaguar, branches from the superior mesenteric plexus were distinctly traced to 

 several parts of the large mesenteric gland ; in other respects, in mammalia generally, 

 the distribution of the superior mesenteric plexus is very similar to that in man, in 

 furnishing the small intestines, and the beginning of the large, with branches, but in 

 being larger or smaller according to the different capacity and extent of the canal, and 

 as it supplies the coecum and the extensive loose portion of the colon in the ass, it 

 appears to preponderate very much more over the inferior mesenteric plexus than it 

 does in some animals. In the ass, the coecum, and about six feet and six inches 

 of the colon, were supplied by the superior mesenteric plexus, and about two feet and 

 six inches by the inferior ; in the baboon, the coacum, and about one foot of the colon, 

 were supplied by the superior, and about five feet by the inferior ; in the fox, about 

 eight inches of the colon were supplied by the superior, and six inches by the inferior. 

 It is difficult to state the precise boundaries of the termination of the superior, and 

 the commencement of the inferior, as the two meet and communicate. But in the ass 

 the superior supplied a much larger portion than the inferior, as compared with the 

 same in the baboon. In the porpoise, from the ganglion in the eighth intercostal 

 space the great splanchnic nerve begins, it passes down a considerable way ; from the 

 prolongation and ganglion in the ninth intercostal space another large branch passes 

 down and joins the preceding near the diaphragm and passes between fibres of this 



