ARTIFICIAL PARTHENOGENESIS IN CUMINGIA 23 



its sections, so as to be sure that it had no polar bodies. Ab- 

 normalities in the positions of the spindles are sometimes found. 

 For instance, in figure 31 the first cleavage has divided the eggs 

 into the unequal cells AB and CD as usual, but the outer pole 

 of the spindle formed in CD for the next cleavage slants away 

 from AB instead of towards it. If the figure were reversed, 

 so that the slant of the spindle were normal (cf. fig. 20), its posi- 

 tion would be abnormal, for it would then lie at the vegetative 

 pole of the egg instead of at its animal pole. There may also 

 be variations in the order of the divisions of the cells, as is shown 

 in figure 33 where D has a spindle developed in a somewhat 

 abnormal position before AB has begun to divide at all. Cleav- 

 age in the parthenogenetic eggs is considerably slower than in 

 the fertilized ones, so that one finds 3- and 4-cell stages in 

 which all the nuclei are in the resting condition. Such stages are 

 not often found in the fertilized eggs where the cleavages suc- 

 ceed each other more rapidly. 



After the 4-cell stage, the cleavage pattern becomes somewhat 

 confused. The 5-cell stage represented in figure 35, for instance, 

 is not at all like the 5-cell stage of the normal egg. This is not 

 illustrated here, but has been described as a cap of four small 

 cells on top of the large cell. The division goes on, apparently 

 without any disturbance of the nucleo-plasma relation, the 

 nuclei being entirely normal in their appearance. No stage 

 was found to correspond to figure 26. Figure 36 shows a par- 

 thenogenetic egg of the same age as the normal one drawn in 

 figure 27. The difference in the size of the cells is undoubtedly 

 due to the slower development of the parthenogenetic egg. 



The surface view of the parthenogenetic larva from an egg 

 without polar bodies has aheady been described, and is shown 

 in text-figure 2, 2. The section of the larva (fig. 28) shows it to 

 be solid, or nearly so, and composed of cells which, though larger 

 than those of a larva from a fertilized egg, are normal in their 

 appearance. There are no organs to be made out, such as are 

 seen in the section of a normal larva of this age. 



Besides these normal cleavage stages, one finds in the pre- 

 served material evidence of a marked tendency towards nuclear 



