2l6 



7 HE BEGINNINGS OF LIFE. 



differed very much in shape and size some were not 

 more than i^Vr'a whilst others were as much as T ^y 





^ 





, Fio. 57- 

 Segmentation of Embryonal Areas into Monads. ( X 1670.) 



a. First stage of differentiation. 



6. Second stage area almost homogeneous and refractive. 



c. First traces of segmentation. 



d. Segmentation more complete units highly refractive. 



e. Units less refractive forming tailless corpuscles. 



/. Fully-developed Monads derived from such corpuscles. 



in diameter. Their shape was wholly irregular. Care- 

 ful examination with a T y and a y immersion ob- 



