io 4 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



diaphragm, the chief respiratory muscle, is far sepa- 

 rated from its nervous segment, but this is due merely 

 to a shifting during development. The Anlage is 

 really located near the head. Such displacements 

 during growth do not take place to this extent in 

 Arthropods. Faivre seems to have been entirely 

 under the influence of current views of Vertebrate 

 physiology, especially those of Flourens, and so he 

 was led into making incorrect statements regarding 

 the physiology of the invertebrates. 



The central nervous system of Limulus consists of 

 the following parts (Fig. 31): A supracesophageal 

 ganglion o, which is usually called the brain, an 

 cesophageal ring (c, Fig. 31) which encloses the oe- 

 sophagus and consists of fibres and ganglia, a sub- 

 cesophageal ganglion u, and the ventral chain with six 

 abdominal ganglia. These parts send out a series 

 of peripheral nerves. In Limulus the situation of 

 the nerve-centres is schematically developed : every 

 peripheral organ has its nerve-centre in that part 

 of the nervous system which belongs to its segment. 

 Perhaps this can be best seen from the following ex- 

 periment made by Miss Hyde : The whole central 

 nervous system of a Limulus was removed with the 

 exception of a little piece of the cesophagus-ring (c, 

 Fig. 31) and the abdominal ganglia (I-VI Abd, Fig. 

 31). No connection remained between these two 

 pieces. The piece of the cesophageal ring lay at the 

 same height with the three mouth-appendages that 

 are used for taking in food. These three mouth- 



