7O LIBBIE H. HYMAN. 



PLATE II. 



FIG. 1 6. Further course of the disintegration shown in Fig. 15. 



FIG. 17. Stage of the early embryonic axis in Tautogolabrus. 



FIG. 18. Same blastoderm as in Fig. 17, drawn without the yolk; it is 

 much shrunken. The embryonic region is disintegrating. 



FIG. 19. Three stages in the disintegration of the earliest observed em- 

 bryo of Fundulus. Anterior end to the left. Disintegration begins at the 

 posterior end, then the anterior end, and proceeds in both directions to the 

 middle. 



FIG. 20. Earliest appearance of the embryo in the cod. Disintegration 

 beginning at the anterior end of the embryonic shield. 



FIG. 21. Further course of the disintegration shown in Fig. 20. 



FIG. 22. Later embryo of the cod ; disintegration beginning at the anterior 

 end of the shield. 



FIGS. 23-26. Further course of the disintegration shown beginning in 

 Fig. 22. 



FIG. 27. An early embryo of Tautogolabrus. Disintegration is beginning 

 at the anterior end of the head. 



FIG. 28. Same embryo as Fig. 27, enlarged, showing course of the disinte- 

 gration along the neural tube. 



FIG. 29. An embryo of Tautogolabrus shortly before the closure of the 

 germ ring. 



FIGS. 30-32. Three stages in the disintegration of the embryo shown in 

 Fig. 29. 



FIG. 33. Normal embryo of Tautogolabrus after the closure of the germ 

 ring. 



FIG. 34. Three stages in the disintegration of the embryo shown in Fig. 

 33. The somites are omitted in the first two drawings. 



FIG. 35. An embryo of Fundulus after the appearance of the optic vesicles 

 and three stages in its disintegration. 



FIG. 36. A later embryo of Fundulus and four stages in its disintegration. 

 The somites are omitted from the latter. The neural tube is characteristically 

 curved. 



