l62 I*. W. BEAMS. 



In Fig. 30 three asters have become attached to chromatin ma- 

 terial, forming a triastral condition with two independent cy- 

 tasters nearby in the cytoplasm. In all cases where cytasters are 

 found associated with nuclear material it is through secondary 

 union. The cytaster is usually much smaller than the nuclear 

 aster, but may vary in size and intensity, as described by Tharald- 

 sen ('26) in Asterias. Usually the larger the number of cytasters 

 present the smaller they are in size. Cytasters never divide unless 

 associated with nuclear material ; neither do they appear till after 

 the breaking down of the germinal vesicle. 



In other cases asters are seen to appear around masses of 

 nuclear material which has failed to vacuolate and fragment in 

 the usual manner. In Fig. 31 a group of asters are present, 

 each of which possesses a portion of the nuclear mass which has 

 failed to be transformed into chromosomes. 



The Effect of the Double Method of Activation on the Matura- 

 tion Divisions. These observations show that the effects of the 

 two activating agents (butyric acid and Loeb's double method) on 

 the maturation divisions of Asterias forbesii initiate similar matu- 

 ration phenomena within the egg. The first activating agent may 

 cause membrane elevation only, or membrane elevation and mon- 

 aster formation together with complete maturation, including its 

 abnormal modifications. The second activating agent may resume 

 the activation process and carry it to completion from any point 

 where the astral phenomena initiated by the single agent halted. 

 Either one of the activating agents may be used without the other, 

 or the hypertonic may be followed by the butyric, or their sequence 

 may be reversed. Also both methods give rise to apparently the 

 same type of abnormal phenomena, including eccentric monasters, 

 triasters, multi-asters, and submerged polar divisions. Eggs 

 treated by Loeb's double method, however, give rise to larger 

 polar spindles, more distinct asters, and produce more rigorous 

 maturation phenomena in general than eggs treated by the butyric 

 method alone. A higher per cent of abnormalities in the matura- 

 tion divisions have been observed to take place after the treatment 

 with Loeb's double method. 



It therefore appears from these observations " that from the 

 point of view of astral phenomena, the two agents are not in dif- 



