270 



ANIMAL BIOLOGY. 



[Part II. 



A stomato-gastric system innervates the crop and gizzard. The 

 recurrent nerve comes into relation with anterior and posterior 

 stomato-gastric ganglia (C, a. stg.^p. stg.}) the former of which is 

 connected with the ventral surface of the hemispheres. Then 

 running backwards along the dorsal surface of the crop, the re- 



aii.1. 



D 



FIG. 82. COCKROACHBRAIN, ETC. 



A. B. C. Head of cockroach opened so as to expose the brain A. from the 

 front ; B. from the side ; C. from above (after E. T. Newton). D. Nerve- 

 chain. 



an. Antennary nerve, an. I. Antennary lobe. a. stg. Anterior stomato- 

 gastric ganglion, con. Commissure to thoracic ganglia. /. g. Frontal 

 ganglion. Ji. s. Hemispheres of brain, la. Labial nerve. lb. Nerve to 

 labrum. mn. Mandibular nerve, mx. Maxillary nerve, n. w. s. Nerve to 

 white spot. op. Optic nerve, p. stg. Posterior stomato-gastric ganglion. 

 r. n. Recurrent nerve, s. ce. Suboesophageal ganglion. 



current nerve, about the middle of the crop, enters the apex of 

 a triangular ventricular ganglion. From the lateral angles of this 

 triangle nerves pass backwards and downwards on either side of 

 the crop, and, breaking into branches, innervate this organ and 

 the gizzard. 



Each coalesced pair of ganglia has to some extent independent 

 control over its somite and appendages. The general co-ordina- 



