Penetration of Marine Tissues by Alkali. 143 



any alteration in function occurs. Even though NH4OH enters readily it 

 is too weak an alkali to affect the cell immediately. 



Pennaria tiarella. 



The tentacles were stained in neutral red and the time for color change 

 was compared with the time required for spontaneous movement to cease. 

 Globules much like those occurring in Cassiopea take up the dye. They are 

 present in all parts of the tentacles. It is probable (but can not be stated 

 positively) that stained granules are present within muscle-fibers. 



In NaOH of any concentration movement always ceases long before any 

 red granules are turned yellow. 



In N/iooo NH4OH movement ceases in about 15 minutes. The red 

 begins to change, but is not completely yellow at this concentration for a 

 long time. In N/500 NH4OH movement ceases before the color change is 

 complete. 



The above results were also obtained using the gill muscles and tentacles 

 of an unidentified Amphitrite-Vike annelid from Tortugas, Florida. 



Salpa democratica. 



Red-stained granules undoubtedly occur within the muscle-fibers of the 

 circular bands of this animal. 



In NaOH of any concentration movement ceases before the color change. 



In N/iooo NH4OH contractions cease in about 15 minutes. The color 

 change begins in 5 minutes, but is not complete even after an hour. In 

 N/500 NH4OH contractions cease before the color change is complete. 



CILIA AND MODIFIED CILIA (CTENOPHORE SWIMMING-PLATE). 



Beroe ovata. 



Granules stained in neutral red occur in the swimming-plate cells, not 

 in the plates themselves. 



In NaOH the movement always ceases long before the color change 

 occurs. 



In N/500 NH4OH, the plates cease beating at first, begin again in less 

 than a minute, but have mostly stopped in 5, and all by 10 minutes. The 

 red granules are only partially yellow even after 45 minutes, although the 

 color change begins in the course of 3 to 4 minutes. 



ToXOPNEUSTES LARViE. 



Red granules occur in the ciliated cells, but not in the cilia themselves. 



In NaOH the cilia always stop before the color change occurs. 



In N/500 NH4OH color change occurs in i to 2 minutes. Movement is 

 stopped at first, begins again in about 4 minutes, continues slowly after 

 half an hour, and has not entirely ceased even after an hour. 



A similar result is obtained with palolo trochophores (Eunice fucata) . 



These experiments with marine cilia agree in every way with those ob- 

 tained on Paramcecium. 



