A. R. MOORE 



203 



capable of more powerful action than the muscles of the top sheath. 

 It is also clear from the results of strychninization and nicotinization 





''^■^r^ 

 ^^■^■y^^ 



^■i 





f-,i-v. ■■•.■■.*. :c-.c-.:i.! • 



-owM^ 







^:.c- .i ■. •.■•.>3 



ii;W-^1? 









Fig. 4. Initial stage in nicotinization. The effect of the nicotine is the reverse 

 from that of strychnine, since the arms bend toward the ventral side and raise 

 the central disk from the floor. 



N^ 







ifti^ 



>»i..-..v .T ■• • -• •: •. 





Fig. 5. Final position resulting from nicotinization. The arms are bent 

 towards the ventral side to such an extent that the ventral surface of the animal 

 is no longer seen; the animal falls on its side. 



that the ventral floor of the ray contains muscle groups which act 

 antagonistically. If we assume both these drugs to act upon the 

 nervous elements controlHng this musculature, we may regard strych- 



