302 KING. [Vol. XVII. 



disintegrating substance to the periphery, is brought about by- 

 some rearrangement in the distribution of the yolk and cyto- 

 plasm which shows itself only in its results. 



With all methods of fixation, there is found at the side of 

 the germinal vesicle nearest the center of the Q.gg an accumu- 

 lation of a granular substance, which, as before stated, has 

 exactly the same appearance as the perivitellin. Under a low 

 power (PL XXVIII, Figs, i, 3) this substance contrasts sharply 

 with the rest of the contents of the Q.gg ; but under an immer- 

 sion lens it is found to be connected with the reticular cyto- 

 plasm extending throughout the ^gg. Born ('94), in describing 

 the ovarian ^gg of Triton with a diameter of not more than 

 90 \JL, says : " Im Eiprotoplasma tritt dicht um den Kern 

 eine besondere kornigfadlige Schicht auf, so dass man mitunter 

 Miihe hat, die feine Kernmembran zu erkennen." As this 

 substance is found in the eggs of Triton and Bufo before the 

 germinal vesicle has attained its full size, I cannot agree with 

 Goette and Schultze that it is a part of the granular nuclear 

 sap forced through the membrane by shrinkage of the vesicle 

 during its dissolution ; nor do I believe with Jordan that it is 

 due to osmotic action during the processes of killing and hard- 

 ening. Whatever its nature, this substance seems to play an 

 important role in the changes accompanying the dissolution of 

 the germinal vesicle, and it is certainly a normal structure in 

 the toad's ^gg, if not in other amphibian eggs. 



There seems to be some question as to whether the large 

 space often found around the germinal vesicle in preserved 

 amphibian eggs is normal or not. According to Fick : " Die 

 scharfe Begrenzung, sowie zum Theil auch die rundliche Form 

 und endlich die ziemlich konstante Grosse der Hohle, sprechen 

 entschieden dagegen, dass es sich hier nur um eine Kunstpro- 

 dukt handelt." On the other hand, Schultze, Hertwig, van 

 Bambeke, and Jordan believe this space to be an artificial 

 product of the reagents used in killing and hardening. 



To determine this point definitely for the toad's &gg, a num- 

 ber of ovarian eggs from the same female were intentionally 

 left in the different killing and hardening fluids varying lengths 

 of time and the effects noted. In eggs badly preserved the 



