PEOTOCOCCOIDE^. 



49 



into 16 new ones (Fig. 45 B), each forming a new individual, 

 which soon grows to the size of the mother-individual. It was 

 in this Alga that the conjugation of self-motile gametes was 

 first discovered by Pringsheim, 1869. When conjugation is 

 about to take place, each cell divides into sixteen, as in vegeta- 

 tive reproduction, but the 16 x 16 cells all separate from one 

 another (Fig. 45 (7, female gametes, and _D, male gametes), and 



FIG. 45. Pandorina morum. 



swarm solitarily in the water. The male are, most frequently, 

 smaller than the female, but otherwise they are exactly alike ; 

 they are more or less pear-shaped, with a colourless anterior end, 

 2 cilia, a red " eye-spot," etc. After swarming for some time they 

 approach each other, two and two, generally a large and a smaller 

 one, and come into contact at their colourless end; in a few 

 moments they coalesce and become one cell (Fig. 45 E, .F), this 



