GALVANOTROPISM 



41 



is sent through a trough containing larvae of a salamander 

 (Amblystoma) the legs and head of the larvae assume 

 definite positions depending upon the direction of the 

 current. When the current goes from head to tail the 

 legs are pushed backward and the head is bent (Fig. 10) ; 



FIG. 10. Forced position of Amblystoma larva under influence of galvanic current 

 oing through animal from head to tail. Head down, body convex on dorsal side. Legs 

 ackward. (After Loeb and Carrey.) 



when the current goes from tail to head the opposite 

 position is observed (Fig. 11). The analogy with the 

 observations on Palamonetes is obvious. 



Galvanotropic reactions are found throughout the 

 whole animal kingdom and the following observations 

 made by Bancroft on a jellyfish (Polyorcliis penicillata) 



Fio. 11. Forced position of A mblystoma larva , when current goea from tail to head. Head 

 raised, legs pushed forward, tail raised. (After Loeb and Carrey.) 



are of especial interest. 10 Strips containing tentacles and 

 the manubrium were cut out from the animal and put into 

 a trough through which a current flowed of 25 to 0.200 

 m. a. for 1 square mm. of the cross section of the liquid 

 (dilute sea water) in the trough. 



