DETAILS OF EARLY EMBRYO. 



8l 





B 



n 



•■■-■V / 



»--<SSl!S!I*5>Ws' 



•"If"/!' ■ "v 



n n 



~^^ 



Figs. 71 A-E and continued F-l on page 82. — Transverse sections of late gastrula shown in Plate V, fig. 36. The sections pass 

 forward ; the first of the series. A, traverses the tail folds; the last, I, the head region of the early embryo. 



0» Tongue of mesoblasl cells representing the urogenital aniage ; (>, megaspheres in process of passing through the yolk-entoblast ; fjc, body cavity; 

 c, points in extra -embryonic region where the ectoderm cells are being proliferated into the blastoderm ; ;/. gut cavity ; "'» megasphere appearing 

 in peristomial mesoblast. 



