35 



( part outside of shell, tlack. 

 Iron-Haematoxylin ) 



( part inside, 'brown except the central "body 

 ) which is hlaok. 



Koltzoff '06 claimed that the sperms. In certain decapods 

 settled on the egg with the nuclear cup towards the egg and the 

 capsule pointed away from the egg. He was also of the opinion 

 that the rehound from the explosion of the capsule was suffi- 

 cient to drive the nucleus Into the egg. On eggs taken from 

 the ovary of Menippe mercenaria, I found a few sperms attach- 

 ed as shown in Fig. 96 with the nuclear cup next to the shell 

 of the egg. That the eversion of the capsule does not force 

 the nucleus through the shell in this case is shown in Pig. 

 97, where a sperm has exploded with the nuclear cup against 

 the egg. So far as my ohservations go there is no evidence 

 whatever that the eversion of the capsule causes any sudden 

 movement of the sperm hody as a whole. 



The niimber of sperms that have pierced the shells of the 

 eggs is much greater for eggs taken from the oviduct than for 

 those taken from the lumen of the ovary. The ntimher was count- 

 ed In a few eggs that had Just heen spawned and the number 

 per egg was as follows: 28,44,52,52,54, 71, 73 and in one ex- 

 ceptional case 679. 



So far there seems to "be no doubt as to the behavior of 

 the sperm in entering the egg, but we may ask; Is this the 

 final stage in the entrance of the sperm? Is not the nuclear 

 cup drawn through the shell at a later stage? If it is not 

 what becomes of it? 



That the nuclear cup does not enter the egg^ but falls 

 off is shown in Figs. 98 to 101. Here we see that the nuclear 



