THE BEGINNINGS OF LIFE. 471 



and vibratory contractions.' After a time the cyst is 

 ruptured, and then the granular embryo c after a few 

 very wry contractions, at once widely opens a large, 

 ciliate mouth, gaping across the sphere's surface ; and 

 disengaging or displaying a girdle of cilia round the 

 rear part of the body, it immediately represents the 

 free-roving Vorticella in full equipment V M. Pouchet, 

 moreover, depicts 2 vesicles gradually increasing in 

 size, which ultimately became converted into Vorti- 

 cellx; and lastly, M. Pineau described the mode of 

 origin of Vorticelke from vesicles which had been 

 developed in the pellicle by a process of synthetic 

 heterogenesis, similar to that which gives birth to 

 Paramecia and Kolpodae. These vesicles, after increas- 

 ing in size, first assumed the form of Actinophrys, then 

 of Acinetae, and ultimately became converted into well- 

 developed Vbrticellx 3 . 



In the last-mentioned mode of origin of Vbrticelke, 

 the starting-points were certain vesicles or corpuscles 

 developed from the pellicle, by a process similar to that 

 whereby Monads and Amoebae have been shown to 

 arise both in the pellicle and in other organic aggre- 

 gates 4 . It is now, therefore, of importance to be able 



1 See 'Monthly Journ. of Microsc. Sc.,' Nov. 1871, p. 229; and Silli- 

 man's 'American Journ.,' Aug. 1871. 



2 ' H&erog&iie,' PI. I. 

 8 See p. 252. 



* It has, moreover, been fully proved that such mere motionless cor- 

 puscles, as well as Monads, Amoebae, and Fungus-germs, are all inter- 

 changeable and convertible forms of living matter. (See Chap, xvii.) 



