248 



ANIMAL PHYSIOLOGY. 



[LESSON 75. 



FIG. 370. 



Nervous system of Cossus ligniperdt 



tributed from this portion of 

 the nervous system are given 

 to the organs of vision, feeling, 

 taste ; supplying all the organs 

 devoted to special sense. Two 

 branches arise from the anterior 

 (front) portion which terminate 

 in a small ganglion, from which 

 a delicate nerve arises. 



1123. This nerve returns, 

 as it were, and was hence called 

 by its discoverer, Lyonnet, the 

 nervus recurrens, or recurrent 

 nerve ; it is distributed upon 

 the oesophagus and stomach, 

 where it terminates : this is the 

 stomato-gastric (mouth stom- 

 ach), or sympathetic nerve. 



1124. The superior portion 

 of the brain is connected with 

 the inferior or sub-cesophageal 

 ganglion (&), by a pair of nerv- 

 ous chords, widely separated, 

 to admit the oesophagus (d), or 

 gullet, which passes through 

 this divided brain. The great 

 necessity for such an arrange- 

 ment of the nervous system in 

 any animal, by which it is ren- 

 dered imperative that the ali- 

 mentary canal should pass 

 through the centre of the brain, 

 is, that the superior portion of 

 it (the brain) must necessarily 

 be always placed in the vertex, 

 to supply the organs of special 

 sense with nerves. The mus- 

 cles of the jaws, &c., receive 

 their supply of nerves from the 

 inferior surface of the brain, 

 which, by the contrivance re- 



