THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SEVENTH SERIES.] 



No. 2. FEBRUARY 1898. 



XV. — Some Activities of Polar Bodies. 

 By E. A. Andrews *. 



The acceptance of the view that the polar bodies given ofF 

 by the eggs of animals are but imperfect eggs incapable of 

 fertilization, and having no part to play in the development 

 of the true egg, has naturally tended to lessen interest in 

 their fate. That they often remain attached to the e^^g for a 

 long time, and that in certain insects, according to Henking, 

 they may remain within the egg or go back again into it, are 

 facts that have seemed of no moment. 



A recent paper t having shown that in certain Echino- 

 derms the polar bodies as well as the egg are possessed of 

 remarkable powers hitherto supposed to be limited to certain 

 Protozoa, and that the polar bodies soon become, and may 

 permanently remain, fused with the developing egg, makes 

 it of great interest to inquire whether the polar bodies of 

 other animals have such powers and such opportunities for 

 possibly influencing the development of the Qgg. 



It seems that in the star-fish and the sea-urchin the Qgg, 

 both before and after fertilization, acts very like many filose 

 Rhizopods — the protoplasm is seen to project itself out from 



* From the ' Johns Hopkins University Cii-culars,' November 1897, 



pp. 14-16 



t G. F. Andrews, " Some Spinning Activities of Protoplasm," Journal 

 of Morphology, xii., 1897. 



Ann. <& Mag. N. Hist. Ser. 7. Vol. i. 9 



