344 L - H - HYMAN AND A. W. BELLAMY. 



of colonies have a higher metabolic rate than, and are electro- 

 negative (galv.) to, basal hydranths and levels. In the one species 

 tested the apical end of the hydranth is cathodic. 



4. In the hydromedusae tested the metabolic rate and electro- 

 negativity (galv.) are greatest in the manubrium, next in the 

 tentacnlate margin, next in the subumbrellar surface, and least in 

 the exumbrella. So far as tested, manubrium and tentacles are 

 cathodic. 



5. In the ctenophore, Plcnrobrachia, the metabolic rate and the 

 electronegativity (galv.) are highest at the aboral pole and decrease 

 toward the oral pole. No galvanotactic response was obtained. 



6. In Planaria maculata anterior and posterior ends have a 

 higher metabolic rate than the middle ; the anterior end is electro- 

 negative (galv.) to posterior levels. In a current a U-shape is 

 assumed with anterior and posterior ends directed toward the 

 cathode, middle toward the anode. In a polyclad worm anterior 

 and posterior ends and margins were found to be electronegative 

 (galv.) to the middle regions; the galvanotactic response was simi- 

 lar to that of Planaria. 



7. In annelids anterior and posterior ends have a higher meta- 

 bolic rate than the middle and are electronegative (galv.) to it. In 

 Nereis, after being kept in the laboratory, anterior and posterior 

 ends are electropositive (galv.) to the middle. When placed in 

 the current, all oligochsetes tested turn their anterior ends toward 

 the cathode, and the larger forms also bend their posterior ends 

 toward the cathode, the body assuming a U-shaped posture. 

 Nereis, in which the two ends are positive (galv.), assumes the 

 same posture, but with the ends facing the anode. 



8. In frog tadpoles the posterior end has the highest metabolic 

 rate and is electronegative (galv.) to anterior levels. In a current 

 they orient with posterior end directed toward the cathode, ante- 

 rior end toward the anode. 



9. It thus appears that so far as our tests have proceeded that 

 regions of higher metabolic rate are externally negative, internally 

 positive, to regions of lower metabolic rate, and that when placed 

 in a current animals direct those parts positively (int.) charged 

 toward the cathode and those parts negatively (int.) charged to- 

 ward the anode. 



