246 



of Molgula, that the two ends of the heart when isolated are cap- 

 able of rhythmic contraction, but the central part is not. I have 

 verified this result in Molgula. The tunicate heart is also affected by 

 nerve poisons such as curari, and nicotin. (Vide Loeb, Lingle, 

 Krukenbeeg, Schultze.) Such experiments seem to mitigate against, 

 or at least modify, our idea of the myogenic origin of the contraction 

 of tunicate heart muscle. 



The above work was begun during the summer of 1899 at the 

 Marine Biological Laboratory at iWoods Hole, Mass., and was con- 

 tinued during the summer of 1901. It is one of a series of observations 

 on the nervous system of the Tunicata which I hope to publish at 

 some future date. 



New York City, Dec. 28, 1901. (Eingegangen am 19. Jan. 1902.) 



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