'^^'^s of the' 

 ^^^^If fro, I 



"lonociSjv 



of 



^eir \\ 



'a 



'ay 

 the latt 



'IV 



%. 



olutio 





njsofe 



t 



into thewatol' 

 erwhentkcLi 



ist before 



Wli 



't 



the clianges to' 



; 



wCre somei^: 



of the two 



masS; and te^: 

 this state 



I 



I 



ss brown. 



ciroiinfer*" 

 s which lea«'| 



I 



:ich contifl^j, 

 sphere. ^^\ 



chlorop^^l; 



forir.s 



inal-e t»'^ 



I 



iflfi. 





7Y/5 BEGINNINGS OF LIFE. 



389 



way towards the confines of the Sp'irogyra cell, which 

 they pierce before any further elaboration of their 



F 



J 



contents takes place. 



On reaching the cell wall, 

 minute papillary eminence. 



each form puts 

 which, having 



passed 



and some- 



through the wallj expands into a ^ large sac, or bursts at 

 its apex/ The isolated form gradually drags four-fifths 

 or more of its bulk through the openin 

 times so much is dragged through as only to leave a 

 little papillary eminence within — so that the portion of 

 protoplasm seems as if it were entering instead of 

 escaping from the Sptrogyra cell. Whereas in certain 

 cases where a tubular extension is formed, it expands 

 into a delicate cyst of a flask-like or globular shape, 

 outside the cell wall^ and retains the protoplasmic con- 

 tents here until they are ultimately developed into 



Monads 

 Monads 



These, which are much 



larger 



than the 



developed within the Nitella filaments, on 



issuing, move about rapidly for a time by the aid of a 

 strong cilium carried in front like that of Astasia^ and 

 then become stationary. The vesicula, or ^ contracting 

 vesicle,^ which do:^s not appear before they leave the 

 cyst, now becomes very active, the cilium is gradually 

 diminished in size and altogether disappears, and the 

 ' Monad passes into a rhizopodous reptant state, which 

 afterwards becomes actinophorous^ and finally assumes 

 a form indistinguishable from that oi Actlno^hrys soU 

 The developmental changes taking place within these 

 outgrowths, and the subsequent changes which the pro- 



