512 



THE BEGINNIJVGS OF LIFE. 



I 



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



Each of these was densely packed with rather 



stages. 



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 Vorticella, many of 

 them were seen to contain a single large ^egg' or gemma '2, 

 These, however, had the usual delicate wall and more 



^- These organisms were generally about ^J-o" ^^^5 ^7 (tJo" bi'O^^- 

 ^ 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 gemmee thrown 

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

 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 bn-tn 

 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. 



f 



rise to 



^ 



hich bad pr 

 Other obs( 

 same vase W( 

 since they h 

 origin of on 

 Rotifers. 



} With referer 

 Rotifers, 1 may s 

 * the still-cl 

 e^'er)' reason to \ 

 sonie of the larg 



'^^fyoun. 



still »v 



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^'■^«a extern 



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spores were 



