BIOLOGICAL BULLETIN 



OF THE 



noarine 



laboratory 



WOODS HOLE, MASS. 



VOL. LI 1 1 



NOVEMBER, 1927 



No. 5 



ALLEE, W. C., AND 



SCHUETT, J. F. 



CRABB, EDWARD D., AND 

 RUBY, M. 



ANDERSON, LOUISE A. 



FRIEDMANN, HERBERT 



CORRINGTON, JULIAN D. 



GATES, G. E. 



BRINLEY, FLOYD JOHN 



HlLDEBRAND, SAMUEL F. 



CONTENTS 



Studies in Animal Aggregations: The Re- 

 lation between Mass of Animals and 

 Resistance to Colloidal Silver 301 



Polyvitelliny in Pond Snails 318 



The Effect of Alkalies on the Oxygen Con- 

 sumption and Susceptibility of Planaria 

 dorotocephala 327 



A Case of Apparently Adaptive Acceleration 

 of Embryonic Growth-Rate in Birds . . . . 343 



Commensal Association of a Spider Crab 

 and a Medusa 346 



Regeneration in a Tropical Earthworm 

 Perionyx excavatus E. Perr 351 



Studies on the Physiological Effects of 

 Hydrogen Cyanide 365 



Sex Ratio in Gambusia 390 



PUBLISHED MONTHLY BY THB 



MARINE BIOLOGICAL LABORATORY 



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LANCASTER PRESS, INC. 

 LANCASTER, PA. 



AGENT FOR GREAT BRITAIN 



WHELDON & WESLEY, LIMITED 



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Single Numbers, $1.00. Per Volume (6 numbers), S4.50 



Entered October 10 xooa, at Lancaster. Pa., as second-class matter under Act of Congress of July 16 1894 



