Head 



Yolk. Blastoderm. 



Flounder Embryo — 3J days. 



T^^' KuptTer's vesicle. 



Flounder Embryo — 54 days. 



Eye. 



Volk sac. Tail. Notochord. 



Flounder Embryo — 4I days. 



Head 



Flounder Embryo — 5J days. 



Notochord 



Flounder Emiiryo — 6J days. Flounder Embryo shortly before hatching. 



STAGES IN THE DEVELOl'MEN I' OF THE FLOUNDER. H. 



