1 * PHYSIOLOGICAL RRRIKS. 



, l>ut al-o, at I--MM a- concern- locomotive movement-. 

 to the influence of a definite centre of co-ordination the >uhci'>o- 

 phagcal ganglion. The rm-bral ganglion exerts a higher 



Controlling influence OV.T tin- n-t of the system than in Worms. 

 win;: to it- increased inhiliitory power ami to the production of 

 thr yi-m-nil niti-4-lr ton- !' constant partial contraction). 



It i hard to siy \vlirtlier any power of initiation should he 

 aligned to the cerebral ^an-lioii it- removal generally results 

 in the o6M>tion of 8)x>ntaueous locomotion, but this may he due 

 to decrease in uuiM-le-power following upon loss of tonus. 



CRUSTACEA. 



D. J 1 The isolated nervous system of a Phyllopod (A/m* 

 yrotluctut). Thoo-ntral -y>teni is in an essentially primitive 



AN 



--OES.G 



of the anterior part* of the N.-rvous System of J 



after Zaddnch and PeUeneer. 

 A-C 1 . Ctottw for antennar ,,,.1 n. A.N 1 , A.N 2 . An- 



rm. (E8.O. CEwpha^eal ganglion. C.G. Cerebral 

 CI.X. Optic nerve. V.C. Visceral cent r.. 



