19"] YAMANOUCHI—CUTLERIA 457 



almost two-thirds of that diameter 



me 



consideration, almost all of the cases in the gametangia from the 

 2-celled stage to 18-celled stage seem alike. The female gametan- 

 gium, consisting of four rows of cells, becomes mature (fig. 89), but 

 quite often each of the cells in the four rows divides again, so that 

 the gametangium consists of eight rows of cells (fig. 90). 



These numerous nuclear divisions are not simultaneous, but 

 follow in regular order, both those which are transverse to the axis 

 of the gametangium and those which are perpendicular to it, so 



ultimate result is the well known female 

 which is composed of four or eisrht rows < 



almost 



opposite the cells of the neighboring row. Each individual cell 



t> X *^ VXXXi t5 



of the gametangium is a female gamete mother cell. The mother 

 cell contains a large nucleus either in the center or near the inner 

 wall (figs. 90, 92). Plastids are crowded either near the inner wall 

 (fig- 9 1 ) or near the outer side (fig. 92), or lie scattered regularly 

 throughout the whole cytoplasm. The nucleus is in the resting 

 condition. 



When the gametangium is mature, the whole contents of a 

 gamete mother cell become a single female gamete. A portion of 

 the free surface of the mother cell dissolves and forms a pore through 

 which the gamete is discharged. The slow process of discharging 

 the gametes is the same as in the case of the male gametes; first, 

 the cilia of the gametes appear outside the pore, keep waving for a 

 while, and then the female gamete is set free. 



FEMALE 



GAMETES 



gametes 



any time during the day and night. However, so far as the writer s 

 experience goes, while he was making observations at half hour 

 intervals under the microscope, the majority of cases showed that 

 the discharge was most abundant at 5 a.m., and that it continues, 

 though gradually diminishing, until 7 a.m. and then ceases. Occa- 

 sionally there is some discharge at n a.m. and 5 p.m. The motile 



