Activities of Polar Bodies. 



113 



a marked astrosphere-like mass at each end, so that the entire 

 figure is strangely like similar appearances in caryokinesis. 



With exceptional light some of the spin-threads are seen 

 to pass up to the egg-membrane and to branch ; others go to 

 the surface of the egg. Here, as in the starfish, the changes 

 that take place, the making of new processes and the with- 

 drawal and bending of old, make it difficult to represent the 

 actual appearances, even if it were possible to adequately 

 express by black lines the optical effect produced by these 

 clear protoplasmic filaments, which bear as much resemblance 

 to fine spun-glasswork as to any other common gross object. 



In a nudibranch moUusk, Tergipes despectus (?), there are 

 often three polar bodies that remain in close association till 

 the larva is a pyramidal many-celled mass. In some cases a 

 connexion was seen, a changing process or processes, ex- 

 tending between a polar body and the Qgg and between one 

 body and another ; generally the connexion escaped observa- 

 tion, though the bodies acted as if held together. In the case 

 shown in figure 3 the small objects near the largest polar 



body were seen to change position, and may have been either 

 foreign or loose particles, or else enlargements upon filose 

 processes so fine as to escape detection with the 6 ocular and 

 2 millim. objective. 



Similar objects near the next polar body proved to be a 

 group of blunt pseudopodia-like outgrowths borne upon a 

 common stalk. From the remaining polar body similar 

 blunt processes projected in various directions separately, and 

 one very long process extended upward to the egg-membrane, 

 where it branched and seemed attached by its several side- 

 threads. This last polar body also sent out a process that 

 apparently attached itself to the surface of the e,gg, which was 

 still in an undivided state. In other cases blunt processes 



