1913] YAMANOUCHI—ZANARDINIA 9 
Development of female gametangia.—Like the male gametangium, 
the female gametangium arises from a superficial cell of the thallus. 
One of the superficial cells divides, giving rise to a gametangium 
initial and a stalk cell. A second or third division may be inter- 
calated between the first division of the superficial cell and the 

G. 6.—Male gametangia in various stages of development: mitotic figures in 
prophase, metaphase, and anaphase show 22 chromosomes: 4a, one of the superficial 
cells, whose division will result in two gametangium initials; }, first division in a 
gametangium initial; c, 2-celled stage; d, 5-celled stage; e, 7- -celled stage; f, gam 
tangium comprising 8 tiers; g, comprising 9 tiers; h, i, and j show respectively the 
cross section of gametangia of 1, 2, and 4 rows of cells. 
differentiation of the gametangium initial, and in this case, the 
female gametangium has a stalk consisting of two or more cells 
(figs. 1 and 9, a, 6). In rare cases, the female gametangium initial 
develops from a middle cell of a multicellular hair which has arisen 
from a superficial cell, indicating the hair origin of the female 
gametangia. The formation of the female gametangium takes place 
