BIOLOGICAL BULLETIN 



OH THH 



Biological laboratory 



WOODS HOLE, MASS. 



VOL. L 



JANUARY, 1926 



No. T 



CONTENTS 



, MARIK A. 

 COKER, R. E. 



Modification of Development on llir Ha sis of 

 nitjen'iitial Susceptibility to Radiation, II I 



Fauna of Penikcsc Island, 1923 ........... -17 



KATER, J. McA., 



and BURROUGHS, R. D. The Cause and Nature of Encystnient in Poly- 



tomella citri .......................... ; v s 



STURTEVANT. A. H., 



and PLUNKETT, C. R. Sequence of Corresponding Third-chromosome 



Genes in Drosophila melanogaster and D. 

 simulans ............................. 5(1 



HAMMETT, FREDERICK S. Systemic and Sex Determinants of Bone 



Croi.i/i (Mas norvcgicns alhinits) ........ 61 



PUBLISHED MONTHLY BY THB 



MARINE BIOLOGICAL LABORATORY 



PRINTED AND ISSUED BY 



LANCASTER PRESS, INC. 

 LANCASTER, PA. 



AGENT FOR GREAT BRITAIN 



WHELDON & WESLEY, LIMITED 



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



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



Entered October in, 1902. at Lancaster. Pa., as second-class matter under Act of Congress of July 16, 1804 



