Brain of Crayfish 77 



cerebral system, and thus over the behaviour of 

 the animal. 



r 

 .C. 



.C.P.C.L 



?::Vj ; 



SB 



DC 



C.'GB. 





FIG. ii. Horizontal section through the brain of a crayfish. 

 x 40. C.C., corpus centrale ; C.GB., commissure of globuli ; 

 C.PC.L., commissures of protocerebral lobes ; DC., mid-brain ; 

 GB., globulus ; GL., glomeruli ; G.N., ganglionic nuclei; O.D., 

 decussating bundle of optic tract; O.T., optic tract; PC.L., fore- 

 brain ; T.C., hind-brain. (Cat. Physl. Series, Museum Roy. Coll. 

 Surgeons, Vol. II., p. 22.) 



As a consequence of the more complex 

 structural arrangement and development of the 

 central nervous system, and sensory organs in 



