HISTORY OF CHROMOSOMAL VESICLES IN FUNDULUS. 257 



up process must of necessity be reversed at the prophase to a 

 certain extent, and some of the liquid which had been taken in 

 be expelled; as will be described later some shrinkage does 

 actually take place. 



During the transformation as well as subsequent to it two 

 kinds of vesicles can be distinguished on the basis of size in the 

 D series, in the control, and in the A series. The larger ones 

 represent the Fundulus chromosomes and the smaller ones those 

 from Ctenolabrus. Since in these three sets of experiments the 

 eggs and sperm were equally injured (or in the control, were 

 equally uninjured) by the radiation, exactly that result was to 

 be expected in keeping with the findings of Moenkhaus and Miss 

 Morris. The B and C series have contributed little to this phase 

 of the investigation, but the conditions, while more complex 

 there, apparently offer confirmation of the fact discovered by 

 Hertwig that chromatin from radiated nuclei does not take 

 part in the spindle to any great extent after development is 

 initiated; or, as they have described it, the development in a 

 strict sense thus becomes parthenogenetic. It is not to be 

 expected therefore that the sperm chromatin in the case of the 

 radiated B series, nor the egg chromatin in the C series will 

 make any considerable contribution to the development of these 

 hybrids. Such condition is found to obtain at least so far as 

 my study has extended. 



Figs. 8 and 12 represent various nuclear changes during the 

 telophases.. The cytoplasmic constriction begins to cut into the 

 cell at about the time of Fig. 8; Fig. 12 was drawn from a cell 

 in which the division was practically complete. There is very 

 little difference between the latter and the resting stage shown 

 in the next figure. During the telophase, growth of the vesicle 

 continues and the distribution of the chromatin granules takes 

 place. Thus the vesicles become approximated to each other 

 so that finally there remains no space between them and each 

 has conformed to its neighbors in assuming its final shape. Yet 

 at all times they can be seen to retain their distinctly individual 

 character, and in well fixed material the outlines of each can be 

 followed. The figures are inadequate to represent the conditions 

 for they are drawn all at one level, and the advantage that 



