BIOLOGICAL BULLETIN 



OF THE 



flDarine Btolootcal laboratory 



WOODS HOLE, MASS. 



VOL. LIII SEPTEMBER, 1927 No. 3 



CONTENTS 



CASTLE, W. A. The Life History of Planar ia velata 139 



HEATH, HAROLD, AND 



WILBUR, BLAKE C. The Development of the Soldier Caste in the 



Termite Genus Termopsis 145 



BEAMS, H. W. Maturation Phenomena in Artificial Partheno- 

 genesis of Asterias forbesii 155 



FRY, HENRY J. The Cross Fertilization of Enucleated Echina- 



rachnius Eggs by Arbacia Sperm 173 



BOWEN, ROBERT H. A Preliminary Report on the Structural Ele- 

 ments of the Cytoplasm in Plant Cells 179 



INMAN, O. L. A Pathogenic Luminescent Bacterium 197 



BRINLEY, F. J., AND 



BAKER, R. H. Some Factors Affecting the Toxicity of Hydro- 

 cyanic Acid for Insects 201 



GRAVE, BENJAMIN H. The Natural History of Cnmingia tellinoides . . 208 



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