232 EDITH PINNEY 



like effect obtained in a side view of an anaphase plate is not so 

 marked as in Fundulus. 



Figure 8 s a drawing of a much later anaphase of the second 

 cleavage. The same forms appear. A few chromosomes were 

 displaced by the knife in sectioning. Figures 9 and 10 of the 

 fourth and second cleavage stages respectively show the same 

 features. 



No very satisfactory polar views of anaphase spindles were 

 found and no very reliable counts of the chromosomes could 

 be made. Figures 11, 12, and 13 represent such views as were 

 obtained. In these the chromosomes of each polar group are 

 distributed through two sections. The counts are thirty-eight, 

 forty-one, and forty-four, respectively. These are plates from 

 fourth-cleavage spindles. Figures 14 and 15 are similar groups 

 from second-cleavage spindles. One shows forty-four and the 

 other forty-eight bodies. It is apparent that an exact estimate 

 of the number of chromosomes present in a f ertihzed Ctenolabrus 

 €gg cannot be made from this evidence, but the results are given 

 here because it is thought that they are of interest in that they 

 give an approximate idea of the number of chromosomes involved 

 in any cross made with Ctenolabrus. 



The chromosomes from one section of a telophase group are 

 shown in figure 16. The formation of vesicles has already begun. 

 This process is essentially similar to that described by Richards 

 ('17) for Fundulus. The chromatin rod lengthens by the separa- 

 tion of its constituent chromomeres. The end of the rod nearest 

 the pole swells first, indicating that the liquid which they absorb 

 comes from the region of the centrosphere. Figure 17 shows 

 the young nucleus consisting of individual vesicles. I have 

 not tried to discover whether or not these vesicles remain separate 

 during the phases of the resting nucleus. 



Fundulus heteroclitus 9 X Ctenolabrus adspersus cf. 



After comparing the chromosomes of Ctenolabrus with those 

 of this hybrid as Miss Morris has figured them, one is forced to 

 the conclusion that the behavior of these 'bearers of heredity' 



