52 WALTER K. FISHER, 



then lost in the maze of fine nerves, forming a network over the walls 

 of this fore-chamber of the stomach. 



It is from the anterior end of each ganglion that one of the 

 principal visceral nerves originates. This passes directly upward and 

 inward on either side of the dorsal wall of the buccal cavity. It 

 immediately divides into two branches. One of these passes forward 

 and enters the duct of the buccal gland, which it follows back, on 

 each side as the stomatogastric nerve (Stg.N, Stg.N), to be spoken 

 of presently. The other branch passes into the dorsal fold of the 

 pharynx, on each side, where it divides into a forward (spn 1 ) and a 

 posterior (spn) branch. The forward branches follow the two folds 

 forward and downward, while the posterior branches, in a similar way, 

 follow along the base of each fold to the proventriculus. In the 

 pharynx, fine branches (spn") are given off laterally along the septa 

 constricting the crop into lateral pockets. These probably continue, 

 in the oesophagus, but could not be determined. 



The nerve which passes forward after the branching of the main 

 stomatogastric nerve from the forward end of the ganglion, itself 

 branches. One division follows each cluct of the buccal gland, back- 

 ward, while the other continues forward in the folds of the dorsal 

 wall of the pharynx, nearly to the palps. 



The posterior or stomatogastric nerves have a different distri- 

 bution on either side of the body so that they will have to be 

 considered separately. Each lies either free in the lumen of the sali- 

 vary duct (Bg. D) or just to one side of the lumen. The right stomato- 

 gastric nerve (Stg.N) enters the posterior septum of the head cavity 

 at about the level of the ventral wall of the pharyngeal pouch. A 

 prominent branch is given off from the nerve to the anteriormost 

 bend of the alimentary canal, where it divides, one division going to 

 the liver, the other to the intestine (a). The nerve in the septum 

 now branches several times. One division (b) passes through the 

 visceral loop and runs backward toward the heart, in the wall of the 

 aorta. The other main branch passes backward out of the septum 

 through the visceral loop, under the aorta, pursuing a course to the 

 left between the oesophagus and the intestine. A small branch (b 1 ) 

 is given off to the lateral wall of the aorta, and then the main nerve 

 divides into two branches. One (c) passes ventrally to the dorsal wall 

 of the visceral artery, along which it can be followed for some di- 

 stance. The dorsal branch follows the ventral wall of the first anterior 

 loop of the intestine, backward, dividing into two branches (Stg.N 



