Crustacea. 



abdomen. In the abdomen the nerve cord is in plain view 

 when the abdominal muscles have been removed. But in 

 the thorax the cord is concealed in a groove made by the 



Antennule 

 nerve 



Antenna 

 nerve 



Nerve ring 

 around gullet 



Sternal artery 



Ganglion 7 



Anus 



FIG. 49. NERVOUS SYSTEM OF CRAYFISH. 



From Huxley's Crayfish. 



inward projecting framework which supports the muscles 

 which move the appendages. From each ganglion nerves 

 radiate to supply the adjacent muscles and sense organs. 



