PLANT LIFE IN PONDS & STREAMS 



known as Volvox Globator, it may be recognised by 

 its perfectly spherical shape and its characteristic 

 movements in water. Volvox is about 1/25 inch in 

 diameter, and although to the uninitiated it appears 

 to be a single minute plant, in reality it is a colony 

 of upwards of twenty thousand cells. The colony 

 may be considered as being made up of thousands 

 upon thousands of cells, very similar to those of 

 Chlamydomonas, and each one arranged with its 

 pair of little whips directed outwards. 



Within the Volvox sphere we may observe a 

 number, usually one to eight, of smaller spheres. 

 These are so-called daughter colonies which have 

 arisen from the continued division of special cells. 

 They develop, fairly rapidly, into young Volvox 

 colonies, then they burst through the cells of the 

 parent colony, swim out into the water and quickly 

 grow to the size of the Volvox from which they were 

 formed. 



There is another kind of Volvox of a yellowish 

 colour and much smaller than Glohator, the big one 

 is the one we must procure ; it is much more easily 

 studied. 



Certain of the plants we shall find in our pond 

 are so animal-like in their movements, that the 

 microscopist who sees them for the first time may 

 wonder whether we are not mistaken in calling them 

 plants. We have already described the common 

 Chlamydomonas, with its curious jerky method of 

 propelling itself through the water. There is, how- 

 ever, an equally common one-celled, pond-frequent- 



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