IQI2] 



YAMANOUCHI—CUTLERIA 



449 



division, but the conspicuous difference in size appears in the forma- 

 tion of the reproductive organs. 



THE MALE GAMETANGIUM 



Mature 



Male gametangia 



small 



When the male 



bet ore the appearance of game- 

 tangia, the surface of the thai] us 

 bears tufts of hairs here and 

 there in somewhat regularly 

 scattered spots. Later, with or 

 without the association of the 

 hairs, young male gametangia 

 appear. Both the male game- 

 tangia and hairs arise from 

 superficial cells of the thallus. 



The mature male gametan- 

 gium consists of a number of 

 tiers of small cells (the male 

 gamete mother cells), each tier 

 composed of 8 cells, and since 



there 



are more than 22 tiers 



(fig. 4), the output of male 

 gametes from a single game- 

 tangium is about 200. The ma- 

 ture male gamete in the free 

 swimming conditic 

 the gametangium 



— Cutleria 



? ium has an oval bearing a few male gametangia in succes- 

 i / r r> \ , ,, sive stages of development. 



shape (fig. 8, a) and usually con- 

 tains two plastids. Associated with one of the plastids, inside of 

 the lateral face of the plasma membrane near the anterior end, is 

 a red pigment, and in close association with this pigment are two 



of different lengths, the long cilium directed toward the 

 ior end, 4.5 times the long diameter of the gamete, and the 



cilia 



diameter 



gamete 



male 



(figs. 3 and 4). 



