68 A TEXTBOOK OF THEORETICAL BOTANY 



which are linked together by fine strands passing through the middle lamellae 

 (Fig. 46). Each cell is thus very similar to Haematococcus. The whole colony 



EYESPOT 



NUCLEUS 



PYRENOID 



FLAGELLUM 



CHLOROPLAST 



PROTOPLASMIC 

 CONNECTIONS 



Fig. 46. — Volvox roiisseletii. Details of the structure of the vegetative cells 

 which form the periphery of the colony. {After Rich.) 



moves and rotates slowly by the concerted action of the flagella, two of which 

 project through the mucus from the anterior end of each cell. 



Young daughter 

 colony 



Gonidium 



Fig. 47. — Volvox aureus. Entire colony seen in optical 

 section showing the peripheral layer of vegetative 

 cells and a number of enlarging gonidia. 



