FISH FOR EXPERIMENTATION 



365 





JUST FERTILIZED CONCENTRATION OF PROTOPLASM AT POLAR CAP 2 CELL - 



HOUR 



w^- , lf^ 





N \ 



y- 



r 



) 



Si J 



BLASTULA - 3 HOURS 3 HOURS -HP 



10 HOURS 



12 HOURS 



15 HOURS 



18 HOURS 



40 HOURS 



TWO DAYS TO HATCHING 



YOLK SAC- HATCHED 



EARLY DEVELOPMENT 

 OF 



ORYZIAS LATIPES 



THE JAPANESE MEDAKA 



OPTIC VESICLES 



Photographs by L. Koth 



TAIL SOMITES 



