THE BEGINNINGS OF LIFE. 503 



an ovoidal form (Fig. 92, a^ b). The largest of these 

 measured about -i/' in long diameter, and in them 

 no trace of a nucleus was now to be seen, whilst 

 the substance generally had become rather more coarsely- 

 granular (f). In other specimens lying side by side with 

 those already mentioned, the granular mass within 

 the now-thinner envelope began, after some obscure 

 molecular changes, though without previous segmenta- 

 tion, to shape itself into an embryo. This soon displayed 

 characteristic traces of a horny pharynx and two pinkish- 

 red pigment spots (as in j*), whilst slow movements of 

 the mass also became visible. When the thin cyst was 

 ultimately ruptured and the embryo appeared, it was 

 seen to be a Rotifer, possessing the characteristics as- 

 signed by Ehrenberg to Biglena catelUna (g). Many 

 specimens of this form of Rotifer were seen swimming 

 about amongst the filaments, though they were all small, 

 and when in the contracted state they scarcely exceeded 

 in point of size the encysted Vorticells from which 

 they had been derived. None of the individuals were 

 observed to contain distinct ova, and in this respect 

 they differed notably from specimens of the same kind 

 of Rotifer, seen on another occasion — which were not 

 only themselves much larger, but had also been derived 

 from the transformation of a much larger matrix 1. 

 A similar transformation of striated Vorticell^ into 



* See p. 510. In this case, too, many of the 'eggs' produced were 

 slightly larger than the Vorticella-cysts and the embryos into which they 

 became converted. 



