FISHERY BULLETIN: VOL. 81, NO. 2 



U-i 



1«» d » w ^V A 



B 



E 





FIGURE 2.— A. Early maturing stage of the yellowtail flounder with yolk vesicles. B. Early maturing stage acquiring yolk. C. Late maturing 

 oocyte. D. Migrating nucleus of late maturing oocyte. EM = early maturing oocyte, ep = early perinucleolus oocyte, f = follicle cell layer, LM 

 = late maturing oocyte, mn = migrating nucleus, n = nucleolus, nu = nucleus, yd = yolk droplet, yv = yolk vesicle, zr = zona radiata. 



Stage VII— Hyaline (Fig. 3 A): Large (about 400 /un) 

 and irregularly shaped, presumably due to his- 

 tological processing. Nucleus, seen only at the 

 beginning of this stage, is irregularly shaped and 

 located near margin of cell. Early in this stage the 

 yolk globules begin to break up, allowing the yolk 

 to coalesce. At conclusion of this stage, interior of 



cell is completely homogeneous, with no yolk 

 globules or nucleus apparent. Zona radiata is thin, 

 and no radial striations are seen. Follicle layer 

 external to the zona radiata is absent. 



In addition to the above seven developmental 

 stages, there were two types of regressing oocytes: 



346 



