BIOLOGICAL BULLETIN 





flDanne Biological Xaborator^" 



WOODS HOLE, MASS. 



Vol. XXVIII February, 1915 No. 2 



CONTENTS 



PAGE 



LoEB, Leo. Aji Early ^Stage of an Experimentally 



Proditced Jntfaifterine Preg}7ancy a7id 

 the Spontaneous Parthenogenesis of 

 the Eggs in the Ovary of the Guinea 

 Pig ..■'^. ..., '■■'. 59 



Garkev, Waeter E. Some Cryoscopic and Osmotic Data 77 



LoEB, Jacqites. Concerning JBrachef s Ideas of the Role 



of JSIemhrane Formaiion in Fertiliza- 

 tion . . 87 



Just. E. E. A)i Experime-Jital Arialysis of Fertili- 



zatio7i in Platvncreis megalops 93 



Linton, Edwin. Sporocysts in an Annelid.. 115 



Published Monthly by the 

 MARINE BIOLOGICAL LABORATORY 



Entered October 10, 1902, at Lancaster, Pa., as second-class matter, 

 under Act of Congress of July 16, 1894. 



