CHAPTER II 
THE DEVELOPMENT PRIOR TO LAYING 
I. MatTURATION 
Tue phenomena of the maturation and fertilization of the hen’s 
ege are almost entirely unknown. The observations of Holl 
demonstrate only that the wall of the germinal vesicle tends to 
disappear when the follicle is nearly ripe. He also doubtfully 
identified six rod-shaped bodies at the margin of the germinal 
vesicle as the chromosomes of the maturation spindle (Fig. 8). 
5 Bh YY pits a 
3) (Dew " 
ALTE PRO ORE EOC ICOMOS 
DS BIO Me S 9,8 [ls by SES gal oy Gr 
1 GRRE Nel a 
sees 7" 
Raat SESS AS 
lia. 8. — Section of the germinal vesicle and surrounding parts 
of an ovarian ovum of the hen measuring 40 x 85 mm. (after 
Holl). 
Chr., Chromosomes. Gr., Granulosa. G. V., Germinal vesi- 
cle. Z.r., Zona radiata. 
But we have fortunately a very good account of the maturation 
and fertilization of the pigeon’s egg by E. H. Harper, which fur- 
nishes the basis of the following description: 
The wall of the germinal vesicle begins to break down in ovarian 
eges of about 18.75 mm. diameter, the full size of the egg of the 
pigeon being about 25 mm. Part of the fluid contents of the 
germinal vesicle flows out and forms a layer outside the disinte- 
32 
