EFFECT OF EADIUM ON FERTILIZATION 111 



asters, and in many cases, a much greater number. But such 

 asters are not connected with each other by spindle fibers nor are 

 they centers for chromatin masses. In some instances a great 

 number of asters is present but their origin is uncertain. If we 

 assume that each original sperm aster has divided normally, it 

 would be necessary that fifteen sperms entered the egg about at 

 the same time. This number is greatly in excess of any observed 

 case. The extra asters may have arisen de novo. 



Perhaps the most common abnormality is the presence of a 

 great number of vesicles without any aster. In view of the facts 

 just presented, namely, that sperm asters develop when poly- 

 spermy occurs, it is evident that the extra vesicles represent a 

 single sperm nucleus that has divided, or else the egg nucleus, or 

 finally, sperm nuclei that have lost their asters. Figure 33 is a 

 case in point. The only aster present is extremely small. The 

 vesicles, of which there are a great number in the egg, are still 

 intact although the karyomeres have about disappeared, having 

 gone into the spireme form. At this stage we should expect the 

 germ nuclei to fuse but in this case, one hundred minutes after 

 insemination, when the control eggs have already divided, we 

 find no evidence of fusion. Such eggs do not divide but show 

 the very common phenomenon of budding. 



By many observers this phenomenon has been described in eggs 

 that are rapidly degenerating. In the eggs of Nereis, at about 

 the time when cleavage should take place, the protoplasm at the 

 periphery separates off into buds of irregular size and shape. 

 They contain no chromatin unless by chance some of the vesicles 

 are in the region where the budding occurs. The protoplasm of 

 the buds and the region directly contiguous shows marked signs 

 of degeneration, appearing to be more fluid and possessing only a 

 few protoplasmic granules, instead of the closely crowded quanti- 

 ties present in the more normal regions. 



The general effect of the radium radiations on the eggs treated 

 in this manner seems to be more on the protoplasm than on the 

 nucleus. The surface layer is greatly affected and as a conse- 

 quence may fail to extrude the alveolar layer. When division 

 would normally occur, only a budding takes place. If the sperm 



