4 E. E. JUST. 



numerable cases each with a bud of varying size still attached to 

 or just detached from the egg. If insemination takes place before 

 the bud drops off, a membrane separates from the "egg" and 

 never from the bud. Repeated observation puts this statement 

 beyond doubt. I have never seen two membranes on such eggs, 

 nor a single membrane enclosing both egg and bud. The portion 

 within the membrane alone cleaves and develops. The portion 

 outside the membrane never develops; it remains attached to the 

 gastrula until completely disintegrated. In some cases the bud is 

 so much larger than the "egg" that membrane separation takes 

 place from a relatively small disk; the cleavage of such eggs is 

 discoidal ; such eggs never give rise to swimmers. 



If the observer inseminate eggs after the buds drop off, only 

 one member of a pair separates a membrane, cleaves, and gastru- 

 lates, though it may be the smaller. The presence or absence of 

 the egg nucleus is of no consequence for the development of these 

 fragments. 



Any one of three possibilities was thought of as responsible for 

 this phenomenon "of bud formation in the egg of Echinarachnius: 

 (i) staleness of the eggs, (2) the presence of blood, (3) the 

 general deterioration of the sexual products toward the end of the 

 season. Accordingly, in 1918 attempts were made to ascertain 

 which of these factors is responsible for this bud formation. And 

 we may state at the outset that though each factor may contribute 

 to the production of buds, the essential factor is the hypertonicity 

 of the medium. 



If eggs of Echinarachnius are allowed to stand in sea- water for 

 several hours, they slowly undergo changes that eventually lead to 

 their complete disintegration. A portion of these eggs upon in- 

 semination separate membranes many of which are stuck to the 

 swollen cortex. If previous to insemination these eggs be gently 

 shaken, buds are formed from those with swollen cortex. Such 

 inseminated eggs with buds separate membranes only from the 

 " eggs " and never from the buds. These eggs cleave and gastru- 

 late, but the per cent, is always low. Late in the season buds are 

 more easily produced. And throughout the season the presence of 

 blood increases the number of buds formed. 



By far- the easiest method for the production of a high per cent. 



