82 DR. C. F. SONNTAG ON THE VAGUS AND 



splanchnic nerves, lami commiinicantes and lateral branches to 

 the rete mirabile on the thoracic parietes*. 



5. The aortic plexus has a large ganglion. 



6. The rectum and bladder receive small nerves. 



7. There is no perceptible difference in the nerves to the upper 

 and lower part of the intestines, just as 'these parts of the gut 

 merge gradually into one another, and there is no capacious 

 csecum. 



It is, thei-efore, evident that the sympathetic nei'ves differ in 

 many respects from those in the Fissipede Carnivora. 



Swan has also made several generalizations on the sympathetic 

 nerves in the Mammalia, and the conditions described in this 

 paper furnish illustrations of his remarks which, as far as the 

 Carnivora are concerned, were made on a very limited series of 

 animals. 



Summari/ and Conclusions. 



1. In most Carnivora Fissipedia the cervical parts of the vagus 

 and sympathetic nerves are fused. In most cases fusion only 

 affects the cords, but in a few species the ganglia are also united. 

 Fusion consists either of an intimate mingling of fibres or 

 adhesion of sheaths only. 



2. The ganglion nodosum is frequently absent in both the 

 neck and the foramen lacerum posticum ; and the superior 

 cervical ganglion qf the sympathetic is likewise absent in a few 

 species. 



3. No middle cervical ganglion is present, and inferior cervical 

 ganglia are frequently absent. 



4. Sympathetic cardiac nerves are frequently contained 

 entirely in branches of the vagi. 



5. The cardiac plexus is sometimes divisible into superficial 

 and deep parts, but ganglia are uncommon. 



6. Pulmonary nerves may arise from cardiac branches of the 

 vagi, 



7. The plexus gulee varies in complexity. It may be absent. 

 In most species ventral and dorsal cords produced by a varying 

 degree of intermingling of the vagi pass from thorax to 

 abdomen. 



8. The ventral vagus cord supplies the ventral gastric wall 

 and branches run along the lesser curvature to the pylorus. 



9. The dorsal vagus cord supplies the dorsum of the stomach. 

 It ends directly in the cceliac ga,nglia or in one of the offshoots of 

 the solar plexus, or it is diffused throughout the plexus. 



10. The number of ganglia on the thoracic sympathetic cord 

 does n<ot always correspond to that of the intercostal nerves. 



* The 7'ete disseminated tlirougliout the bodj' enables the animal to accommodate 

 itself to variations in the water pressure when it dives or rises to the surface ; and 

 the sympathetic nerves running to the thoracic rete form part of the accommodating 

 neuro-vascular mechanism. 



