512 THE BEGINNIJSfGS OF LIFE. 



in size (/). Other cysts were seen_, representing later 

 stages. Each of these was densely packed with rather 

 coarse yellowish-brown granules ; and, after a time, the 

 whole mass began to shape' itself into an animal organ- 

 ism, irregularly folded^ but presenting all the appearance 

 of being an embryo Rotifer furnished with two red 

 pigment spots. The body had by this time still further 

 increased in size, and the cyst-wall had become pro- 

 portionately thinner, so that, after the usual struggling 

 movements of the embryo, the cyst was at last ruptured, 

 and a Rotifer appeared — notably larger, though otherwise 

 similar to the Diglena ^ which, as we have already seen, 

 may be produced from an encysted Vorticella. The 

 vessel contained multitudes of these Rotifers ; only, un- 

 like the small forms produced from Vorticellse, many of 

 them were seen to contain a single large ^egg' or gemma-. 

 These, however, had the usual delicate wall and more 



^ These organisms were generally about ^50" long by -^^' broad. 



^ I entirely agree with Prof. Cohn concerning the nature of these 

 bodies. According to Pritchard (loc. cit., p. 656), ' Dr. Cohn contends 

 that the bodies ordinarily regarded as eggs are merely gemmae thrown 

 off from the organ believed to be an ovary, without any fertilization by 

 a male animal.' Prof. Huxley, on the other hand, whilst he regards 

 these bodies as eggs ('Trans, of Microsc. Soc' 1853, p. 14), considers 

 some of the so-called ' winter-eggs ' to be real gemmae produced by the 

 individualization of a portion of the ovary. In the face of the obser- 

 vations of Dr. Gros, however, it is important to note that the ' winter- 

 eggs ' described by Prof. Huxley were never seen by him to give birth 

 to a Rotifer. On the other hand, we shall subsequently find that many 

 specimens of the so-called ' winter-eggs ' (found in the free state) have 

 been produced heterogenetically, and not by Rotifers, although they 

 have been seen to give birth to Rotifers. 



