THE BEGINNINGS OF LIFE. 517 



surrounded by adherent Cblorococcus-corpuscles (c). And 

 the membrane having been once formed, minute but 

 densely-packed villous outgrowths soon appeared upon 

 its surface. This membrane gradually thickened, whilst 

 the substance of the egg became a little less opaque, and 

 after a time the internal contents separated from one 

 end, so as to leave a space between the thick outer shell 

 and the inner membrane by which the evenly granular 

 embryo mass was now enclosed (/). Later still 1 the 

 embryo mass becomes lighter and more refractive, 

 whilst it is seen to move within the cyst, and the play 

 of its ciliary wreaths may also be distinguished though 

 with some difficulty, on account of the opaque nature 

 of the cyst in which the embryo is contained. When 

 the cyst is ultimately ruptured, a well-organized speci- 

 men of Hydatina senta makes its appearance. 



Concerning the reality of all these transformations, 

 astounding as they are, I now entertain not the slightest 

 doubt. And, in addition to having traced all the stages 

 by which the heap of Chlorococcus-corpuscles becomes 

 transformed into an embryo Rotifer, I have over and 

 over again ascertained, from an examination of different 

 portions of the pellicle on the surface or at the sides of 

 the vessel, that the number of the green heaps and of 

 the brown egg-like bodies in different stages was always 



1 The duration of which is uncertain, since, whenever I have attempted 

 to isolate specimens, so as to try to watch their individual development, 

 I have found that the transformative changes were arrested. Similar 

 difficulties have also been encountered in attempting to watch the 

 development of other forms, (See also Gros, loc. cit., pp. 334-337-) 



