196 



Chlorophycece 



dioecious. The most thorough investigations of the life-history 

 of the genus have been made by Klein 1 . 



This genus is the culminating point in the evolution of motile 

 coenobic forms, and although the individual cells are of the 



Fig. 78. A, C, and D, Volvox aureus Ehrenb. A, monoecious sexual colony ( x 210), 

 from Bawclitfe Common, W. Yorks. ; D, ripe oospore (x475); C, two anthero- 

 zoids (after Klein). B, ripe o'ospore of V. globator (L.) Ehrenb., from Preston, 

 Lancashire ( x 475). a, androgonidia ; an, antherozoid ; g, gynogonidia. 



primitive Chlamydomonadine type, the entire organism, by reason 

 of the differentiation of its component cells, has attained along its 

 own line a state of evolution quite comparable with the structural 

 differentiation attained along other lines by the highest known 

 forms of the green Algae. 



The Rotifer Notommata parasitica sometimes occurs as a 

 parasite within the hollow coenobia of Volvox, swimming about 

 within the central cavity and feeding on the green cells either of 

 the adult or of the parthenogenetic daughter-coenobia. 



1 Klein 'Morphol. u. biol. Studien iiber die Gatt. Volvox,' Pringsh. Jahrbiich. f. 

 wissensch. Bot. 1889, Bd xx. 



