BIOLOGICAL BULLETIN 



OF THE 



fiDarine Biological laboratory 



WOODS HOLE, MASS. 



Vol. XLIV 



April, 1923 



No. 4 



CONTENTS 



■&&*********% 



4 £?fii 



McNair, George T. Motor Reactions of the Fresh-Water*, Sponge, 



i I 



Allee, W. C. 



Lambert, W. V., 

 Rice, W. S. and 

 Walker, H. C. A. 



Ephydatia fluviatilis .... X^^&j/, • 153 



Studies in Marine Ecology. I, The Distribution 

 of Common Littoral Invertebrates of the Woods 

 Hole Region. . . '. ... . . . . . 167 



Food and Partheno genetic Reproduction as Relat- 

 ed to the Constitutional Vigor of Hydatina senta 192 





Published Monthly by the 



MARINE BIOLOGICAL LABORATORY 



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Entered October 10, 1902, at Lancaster, Pa., as second-class matter under Act of Congress of July 16 i894- 



