ARTIFICIAL PARTHENOGENESIS IN CUMINGIA 5 



spindle moves nearer to the periphery of the egg, the eighteen 

 chromosomes divide, and a normal anaphase ensues (fig. 3). 

 The cytoplasm of the egg pushes out to form the first polar 

 body, and the first maturation mitosis is completed (fig. 4). 



The second maturation division follows without the interven- 

 tion of a resting stage (fig. 5). During the formation of the 

 second polar body, the first is often pulled back into a concavity 

 of the surface of the egg, so that it would be invisible in a sur- 

 face view, but the walls between the two cells remain intact. 

 Such a condition is represented in figure 7, but in figure 6 we 

 see a very different case in which the first polar body and the 

 cytoplasmic bud for the second both stand out prominently be- 

 yond the surface of the egg. The second polar spindle (repre- 

 sented in figures 6, 7, and 9) is rather smaller than the first, but 

 is like it in having eighteen chromosomes which divide and go 

 to the poles of the spindle in a perfectly normal manner (fig. 9). 



The chromosomes in the two divisions are, however, quite dif- 

 ferent in form. Those of the first maturation are varied in 

 shspe and size, but are all larger than those of the second polar 

 spindle. No regular series can be made of them, as has been 

 done with the chromosomes of some other forms. The two 

 clearest equatorial plates of this spindle that were found are 

 represented in figures 2a and 2b. They are alike in having two 

 rings and one U-shaped chromosome apiece, but one could not 

 say whether these forms are constant without much more study 

 of the point than seems worth while in the present connection. 

 The remaining fourteen chromosomes of the first polar spindle 

 are round, oval, or cross-shaped bodies of various sizes. At the 

 beginning of the anaphase, as soon as the arrangement in a 

 regular plate is lost, the chromosomes undergo a marked reduc- 

 tion in size. The daughter-chromosomes of the anaphase (fig. 

 3) seem less than half as large as the chromosomes of the equa- 

 torial plate. 



The equatorial plate of the second polar spindle is repre- 

 sented in figure 8. Here the chromosomes are all in the form 

 of short rods with somewhat irregular outlines. They are much 

 more constant in size and shape than those of the fu'st polar 

 spindle. 



