JV CONTENTS. 



KTERSKOG-AGERSBORG, H. P. Bilateral Tendencies and Habits 

 in the Twenty-rayed Starfish Pycnopodia helienthoides (Stimp- 

 son} 232 



No. 5. NOVEMBER, 1918. 



GEORGE, \V. C. Experiments on the Determination of the Fate of 



the Gray Crescent Material in the Frog Egg 255 



HOSKINS, MARGARET MORRIS. Further Experiments on the Effect 



of Heat on the Eggs of Cumingia 260 



BEHRE, ELLINOR HELENE. An Experimental Study of Acclima- 

 tion to Temperature in Planaria dorotocephala . . . . 277 



No. 6. DECEMBER, 1918. 



BARTELMEZ, GEORGE YV. The Relation of the Embryo to the Prin- 

 cipal Axis of Symmetry in the Bird's Egg 319 



PATTERSON, J. T. Studies on the Biology of Paracopidosomopsis . 362 



