CONDITIONS ASSOCIATED WITH FERTILIZATION PROCESS 



3. Merogony 



265 



Merogony is the development of part of the egg. that is, an egg fragment. 

 Egg fragments are obtained by shaking the egg to pieces, by cutting with a 

 sharp instrument, or by the use of centrifugal force. Andromerogony is the 

 development of a non-nucleate egg fragment after it has been fertilized by 



Fig. 133. Stages in the fertilization of Ascaris. (After Boveri, 1887.) (A) Ameboid 

 sperm on the periphery of the egg; germinal vesicle in center of primary oocyte. (B) 

 Sperm entered egg substance; germinal vesicle broken down and tetrads becoming evident. 



(C) Sperm in center of the egg; first maturation division, showing tetrads on spindle. 



(D) Second maturation division; first polar body at egg's surface. (E) First and second 

 polar bodies shown; sperm aster forming in relation to sperm. (F) Second polar body; 

 male and female pronuclei. (G) Male and female haploid chromosomes evident; 

 amphiaster forming. (H) Chromosomes distinct, showing haploid condition. Observe 

 amphiaster. (I) Amphiaster complete; metaphase of first cleavage. 



