THE BEGINNINGS OF LIFE. 385 



ascend, and the tube itself gives up its contents to 

 the globule. The latter is often about -gfa" in 

 diameter; its substance, perfectly homogeneous and 

 much more refractive than water, remains quite mo- 

 tionless. But this stage of rest is one of short du- 

 ration, and scarcely two minutes elapse before the 

 different refractive powers of different portions of the 

 contents show that a change is taking place. Signs 

 of the internal differentiation of globular portions of 

 the contents soon become evident, and grow more and 

 more distinct. At last movement recommences no 

 mere displacement of the liquid, but an actual swarm- 

 ing movement of the spherical portions into which the 

 contents have been resolved. The movements of the 

 bodies about fifteen or twenty in number increase 

 in extent and rapidity, till at last the envelope bursts 

 and gives exit to these active units as ciliated or- 

 ganisms, similar to those which were included in the 

 genus Trtchomonas by Dujardin (g). Their bodies after a 

 time become nodulated, and about a-sVtr" i* 1 diameter. 

 They are somewhat irregular in shape, and are pro- 

 longed at one extremity into a well-marked flagellum, 

 at the base of which and on one side seven or eight 

 cilix are situated. At the opposite extremity of the 

 body there is a much shorter prolongation. 



' gonidial-cells ' of Chara. Mr. Archer believes them to be normal, 

 though very unusual, 'zoospores' of the Desmid in question. Much 

 doubt, however, still hangs over the subject. It seems to me more likely 

 that they are heterogenetic products, and that they do not at all belon 

 to the natural developmental cycle of the plant. 

 VOL. II. C C 



