72 AMPHIBIA. 



PLATE XIX. 



THE SYMPATHETIC NERVE OF THE SNAKE. 



(BOA CONSTRICTOR.) 



THIS view is taken from about the middle of the body of the same snake as in 

 the preceding plate. The sympathetic is seen communicating with each spinal nerve, 

 and then sending filaments on the membrane connecting the viscera with the spine 

 and ribs, some of which are distributed on it, and continued as far as the fat contained 

 in its anterior folds, whilst others pass to the viscera, bloodvessels, &c. 



a. Aorta ; b. Vein receiving blood from the intercostal spaces ; c. Gall duct. 



1. Right division of the par vagum a little before its termination on the stomach. 



2. Sympathetic nerve. 



Without previous preparation, it is impossible to observe the extreme complexity, 

 delicacy, and extent of the branches of the sympathetic in the snake. They present 

 one of the most wonderful displays of minute structure that can be observed. In the 

 recent state of the animal, the nerves from just below the head are so transparent, 

 as to be with great difficulty distinguished from the surrounding parts ; but after the 

 animal has been opened through its whole length, and the connecting membrane of 

 the viscera separated to a little distance from the margin of the ribs ; after it has been 

 immersed in water for a few hours, and then in spirits, or a solution of oxymuriate of 



