BIOLOGICAL BULLETIN 



OF THE 



fiDarine Biological laboratory 



WOODS HOLE, MASS. 



VOL. LI 1 1 



OCTOBER, 1927 



No. 4 



HORNING, BENJAMIN, AND 

 TORREY, HARRY BEAL 



CHAMBERS, ROBERT, AND 

 POLLACK, HERBERT 



BASKERVILL, M. L. 



DIECKMANN, JOHANNA M. 



DIECKMANN, JOHANNA M. 



WHEDON, ARTHUR D. 



CONTENTS 



Thyroid and Gonad as Factors in the Pro- 

 duction of Plumage Melanins in the 

 Domestic Fmd 221 



The pH of the Blastoccele of Echinoderm 

 Embryos 233 



The Permeability of Frog Skin to Urea: 



I. The Influence of NaCl and CaClz 239 

 //. The Effect of Dextrose and Sucrose . . 247 



The Cloaca and Spermatheca of Gyrino- 

 philus porphyriticus 258 



The Cloaca and Spermatheca of Hcmidac- 

 tylium scntatitm 281 



The Structure and Transformation of the 

 Labiitm of Anax jnnius 286 



PUBLISHED MONTHLY BY THB 



MARINE BIOLOGICAL LABORATORY 



PRINTED AND ISSUED BY 



LANCASTER PRESS, INC. 

 LANCASTER, PA. 



AGENT FOB GREAT BRITAIN 



WHELDON & WESLEY, LIMITED 



2, 3 and 4 Arthur Street, New Oxford Street, London, W. C. 2 



Single Numbers, $1.00. Per Volume (6 numbers), S4.5O 



Entered October 10 1903, at Lancaster, Pa., as second-class matter under Act of Congress of July 16 .1894 



