THE BEGI.YNINGS OF LIFE. 515 



originally described by Ehrenberg, who recognized that 

 the process of development went on within them at a 

 much slower rate than it did within such large ova or 

 gemmse as are ordinarily produced within the adult 

 animal. These gemm.se also possess a smooth trans- 

 parent and very thin envelope_, whilst in the so-called 

 <^ lasting or winter-eggs' the external surface is ^ hairy' 

 or villous, and the envelopes are double, in addition to 

 being much thicker and more opaque. 



After some careful investigation, I ultimately ascer- 

 tained that every intermediate stage was to be seen, be- 

 tweenthe spherical or ovoidal heap of green Chlorococcus- 

 corpuscles (Fig. 93, a) and the fully-formed winter-egg 

 containing an embryo Hydatina, whose ciliary wreaths 

 were in full activity. The steps of the transformation 

 were as follows : — The mass of aggregated algoid vesi- 

 cles assumed a preternaturally bright-green colour, and 

 some of the corpuscles seemed to fuse with one another, 

 owing to a solution of their thin envelopes — so that the 

 masses after a time presented a more granular appear- 

 ance. Decolourization then seemed to commence 

 and pr-oceeded rapidly throughout the po"tion of algoid 

 matter which was destined to form the future 'egg' 

 —always involving an ovoid mass about -^\-^" in 

 diameter. The external limits of this transformation 

 were always sharply defined, and 1 have seen many 

 bodies in this early stage in which the future o^gg was 

 represented by an opaque ovoidal mass of rather dark- 

 brown granular matter, to which no bounding membrane 



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