THE CONVERSE RELATION BETWEEN CILIARY AND NEURO- 

 MUSCULAR MOVEMENTS. 



By Alfred Goldsborough Mayer. 



This research was commenced at Tortugas, Florida, during the 

 summer of 1909, and was continued in the Marine Biological Laboratory 

 at Woods Hole, Massachusetts, and also at the New York Aquarium. 

 I am greatly indebted to Prof. Charles R. Stockard of Cornell Medical 

 College, Prof. Frank R. LilHe, Director of the Marine Biological Labo- 

 ratory at Woods Hole, and Dr. Charles H. Townsend, Director of the 

 New York Aquarium, for their kind aid in gathering and maintaining 

 material alive for the research, and for granting to me the excellent 

 facilities of the Woods Hole Laboratory and of the New York Aquarium. 

 To Professors Carlton C. Curtis, of Columbia, and Roland Thaxter, of 

 Harvard, I am also indebted for some highly appreciated advice upon 

 the botanical side of the research. 



Preliminary reports of the present research were published in the 

 Biological Bulletin, Woods Hole, vol. 17, pp. 341, 342; in the Proceed- 

 ings of the Society for Experimental Biology and Medicine, 1909, No. 7, 

 pp. 19, 20; and in the Year Book of the Carnegie Institution of Wash- 

 ington for 1909, p. 152. 



CONCLUSIONS NEW TO SCIENCE. 



The effects of the several cations of the blood-salts, sodium, mag- 

 nesium, calcium, ammonium, potassium, and hydrogen upon neuro- 

 muscular movements are in each case the exact opposite of their effects 

 upon the ciliary movements of animals. 



There is wide diversity in the reactions of various species of motile 

 fungi and algae to these ions, and the statement made in the preceding 

 paragraph applies only to animals. 



Ordinary ciliated epithelium such as that covering the external 

 surface of Trematodes is not wholly under the control of the nervous or 

 muscular system of the animal, and the cilia continue to beat even when 

 the muscles underlying them contract. 



The more highly specialized cilia, however, such as those of the 

 meridional combs of Ctenophores, the lobes of veliger larvae, the peris- 

 tomial ring of trochophores, or the longitudinal band of Semper's actinian 

 larva, cease to beat when the muscles underlying them contract, and 

 resume their rhythmic movement only when the muscles relax. Thus 

 an electrical stimulus which causes the muscles to contract stops the 

 cilia, but if the muscles be anesthetized with magnesium so that they 



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