242 THE ROYAL SOCIETY OF CANADA 



frontal ganglion, the nerve enters the clypeus and enlarges slightly 

 to form a very minute ganglion (g 1) which receives branch c of the 

 clypeo-labral nerve. The frontal nerve then bifurcates and the two 

 branches run forward innervating the muscles of the anterior portion 

 of the pharynx. 



The Recurrent Nerve. (Figs. 1 and 3, r.n.) This nerve 

 originates from the posterior end of the frontal ganglion and runs 

 back along the medio-dorsal line of the oesophagus, passing beneath 

 the supraoesophageal ganglion. Midway between the frontal gang- 

 lion and the brain, the recurrent nerve enlarges into a small ganglion 

 (g3) from which a pair of small lateral nerves arise. These nerves 

 branch near their origin, the branches innervating the dorsal portion 

 of the pharynx. They then pass round the pharnyx and on the under 

 side run forward innervating the ventral side of the pharynx. These 

 nerves probably correspond with the pharyngeal nerves of Hammar. 

 Those which he describes for the larva of Corydalis cornuta, however, 

 originate from the frontal ganglion and not from the recurrent nerve. 



The recurrent nerve continues backward, passing between the 

 oesophagus and the aorta, adhering at first closely to the latter and 

 afterwards to the proventriculus. Throughout its course it gives off 

 many nerves which innervate the alimentary canal and the dorsal 

 vessel. The recurrent nerve terminates in the vagus ganglion. 



The Vagus or Stomachic Ganglion. This is situated between 

 the proventriculus and the dorsal vessel in the posterior region of the 

 second thoracic segment. It is very small and hardly differentiated 

 from the recurrent nerve. 



The Stomatogastric Nerves. The stomatogastric nerves 

 arise from the posterior border of the vagus ganglion. They run 

 obliquely to the sides of the ventriculus and then backward inner- 

 vating the stomach. 



2. THE PAIRED LATERAL SYMPATHETIC SYSTEM. 



This system consists of two pairs of small lateral ganglia (fig. 3, 

 L.G.) situated at the sides of the oesophagus, a short distance behind 

 and to the side of the supraoesophageal ganglia. The two ganglia 

 on either side are connected by an obsolete connective, but the pair 

 on the right side is not connected with the pair on the left. Each pair 

 of ganglia is joined to the brain by a pair of nerves, one of which (p) 

 arises near the base of the optic nerve, and the other (q) from the 

 ventral side of the brain. 



Nerve p. (figs. 3 and 7). Starting from the lateral ganglion, nerve 

 p runs inward and forward and unites with the supraoesophageal 



