PLATE IV. 

 Fig. 42 A. — Median section of germ disc of ca. 49 hours. X l^-- 

 Fig. 42 B. — Posterior portion of the same section. X 300. 



Figs. 43 A-C. — Portions of cross sections of an egg of ca. 49 hours ; A, in 

 midline anterior to anterior cumulus ; B, in lateral region ; C, at posterior 

 cumulus. X 360. 



Fig. 44. — Surface view of unstained germ disc of ca. 49 hours, seen in 

 alcohol. X 30. 



Fig. 45. — Ventral view of germ disc with 4 protozonites, 60l^ hours. X ^0. 

 Fig. 46. — Ventral view of germ disc with 5 protozonites, 60 hours. X 60. 

 Fig. 47. — Lateral view of embryo with 5 protozonites, 60 hours. X 30. 



Fig. 48. — Oblique longitudinal section of embryo with 5 protozonites, 00 

 hours. X 142. 



Figs. 49 A, B. — Portions of cross sections of an embryo of 60i/4 hours; 

 A. through extraembryonic area ; B, through half of the germ disc in the 

 plane of a protozonite. X 360. 



Figs. 50 A-C. — Portions of median sections of germ disc of 00% hours. 

 A, cephalic lobe region ; B, caudal lobe region ; C, through two of the an- 

 terior protozonites. X 300. 



Fig. 51. — Oblique latero-ventral surface view, 00^^ hours, first appearance 

 of appendages, x 60. 



Fig. 52. — Oblique latero-ventral surface view, ca. 02 hours, x 60. 



Fig. 53. — Lateral surface view, ca. 02 hours, x ^- 



