ARTIFICIAL PARTHENOGENESIS IN CUMINGIA 21 



be no significant relation between the number actually found 

 and the haploid or diploid number of the species. The facts 

 are in accord with the idea that Brauer ('94) had from his study 

 of Artemia salina that the number of chromosomes is of no 

 importance in the development of the organism provided the 

 mass of chromatic material is undiminished. 



The achromatic portion of the spindle is very faint in the 

 metaphase of the first cleavage. Figure 64 shows a side view 

 of one of the rings of chromosomes, with a faint aster but no 

 spindle. In the anaphase the figure is better developed and 

 the chromosomes are smal' round bodies (fig. 66). In later 

 cleavages the large number of chromosomes persists and the 

 size is only slightly i;educed. Figure 67 shows a plate of fifty- 

 two chromosomes from the larger cell of a 2-cell stage; figure 

 68, the chromosomes from a middle cleavage stage. 



The eggs undergoing parthenogenetic development often fol- 

 low the normal cleavage pattern so closely that they could not 

 be distinguished from fertilized eggs. Text-figure 3 shows sur- 

 face views of a number of early cleavage stages of parthenoge- 

 netic eggs. Such examples as numbers 1, 3, 5, 8 and 9 are not 

 uncommon in the experiments. Here, as far as one can tell, 

 cleavage is proceeding in a perfectly normal manner. In other 

 cases, the size-relations of the cells have been modified. Often 

 the first two blastomeres are approximately equal in size (text- 

 fig. 3, 2) and sometimes a 3-cell stage is found composed of equal 

 cells (text-fig. 3, 6). Corresponding abnormalities are seen in 

 the 4-cell stage. On the whole, however, the surface views show 

 an approximation to the normal cleavage pattern which is 

 rather unusual in eggs developing by artificial parthenogenesis. 



In the sections of these early cleavages illustrated m figures 

 29 to 35, the normal relations are shown in many cases, and of 

 course the same variations from the normal pattern that were 

 found in surface views are repeated here. Figure 30, for in- 

 stance, shows a 2-cell stage in which the blastomeres are so 

 nearly equal that it was impossible to letter them to correspond 

 to the cells of a fertilized egg. All these drawings are made 

 from slides in which it was possible to trace an egg through all 



