SECT. n. VOLVOX GLOB AT OR. 189 



according to Mr. F. Currey, the exact time is the same 

 in Lapland, where there is no night, and at Berlin in 

 spring when the day and night are almost equal. The 

 fertility is enormous. It is calculated that in eight days, 

 under favourable circumstances, 16,777,216 families of 

 theJStephanosphsera pluvialis may be formed from one 

 resting spore. 



The transmutation of chlorophyll in the Protococcus 

 and Yolvocinese, from green to red and vice versa, which 

 so frequently occurs in the lowest class of plants, shows 

 that its molecules must be united by very feeble affinities, 

 and easily converted into new combinations either by 

 direct chemical action, or by other substances also in a 

 state of change. 



The Volvocinese consist of various species according 

 as the internal matter of the primordial cell divides into 

 2, 4, 8, 32, or a greater number of equal parts, forming 

 respectively as many free cells which ultimately become 

 ciliated spores, by means of which the globe either 

 rotates on the spot, or in straight lines. The Volvox 

 globator found in fresh-water pools is one of the most 

 remarkable of these, both for its 

 peculiarity and beauty of struc- 

 ture and for its comparatively 

 large size, since in some lights 

 it is visible to the naked eye 

 while swimming in a drop of 

 water. When viewed with a mi- 

 croscope, it is a pellucid sphere 

 whose surface is studded with 

 green spots, often connected by Fig . 8t voivox giobator. 

 green threads ; each of the spots 



has two cilia, so that the surface is bristled with these 

 filaments, whose vibrations give the sphere either a 

 rolling or smooth motion, or make it spin like a top in 

 the same place. 



