THE PHYTOZOA. 153 



CHAPTER VIII. 



TUB PHYTOZOA, OR PLANT-ANIMALS. THEIR RELATION TO UNDOUBTED ANIMALS. 



BUT to the test now. One of the most perplexing, and yet 

 exceedingly interesting, of all these doubtful forms, is the so- 



Fig. 92. 



Fig. 93. 



called Globe-animalcule," (figs. 92, 93,) or Volvox, as it is named, 

 on account of its constant revolving motion whilst it progresses 

 through the water. It is a minute, green, globular body, just visi- 

 ble to the naked eye, everywhere in our ponds and ditches, so com- 

 mon among the water-weeds that every dip of the gauze fishing- 

 net collects them in abundance. When observed with a low 

 magnifying power, it resembles a globular net-work (fig. 92) with 

 green spots set in, like emeralds, at the junction of the threads. 



Fig. 92. Volvox glolator. Ehr. 50 diam. The " Globe-animalcule." A speci- 

 men containing four young, of which one (a) is seen in profile attached to the 

 inner face of the hollow globe. Original. 



Fig. 93. Volvox globator. Ehr. 600 diam. A portion of the gelatinous en- 

 velope of a full-grown Volvox, with a very young one attached to its inner face. 

 c 1 , the envelope of the old stock; c, the envelope of the young; c 2 , point of 

 attachment of c to c 1 ; g, g^, the zob'spores of the parent stock; Z, vibratory lashes 

 projecting through c 1 ; # 2 , zoospores of the young with their vibratory lashes 

 projecting through c; w, w l , cell-wall of g, g l : n, n 1 , threads attaching the 

 zoospores to each other. Original. 



