Smith—The Organization of the Colony. 1197 
tures, which have been fixed and stained and found to be bi- 
or tetranucleate, I am inclined to the view that the giant cells 
in question have more than one nucleus. If this be true then 
the more concentrated culture media do not inhibit the divi¬ 
sion of the nucleus but do inhibit the cytoplasmic cleavage that 
normally follows nuclear division. The excessive growth may 
then be a result of the maintainance of the nucleocytoplasmic 
relationship. In colonies composed of giant cells a cleavage 
to form young colonies was not observed. 
Besides causing a formation of giant cells, that apparently 
do not divide, the concentrated culture media also influence 
the shape of the colonies in cells that do divide. Some of the col¬ 
onies, usually those composed of smaller cells, have the normal 
cell arrangement (Fig. 114), although irregularities in this* 
arrangement may occur (Figs. 99 & 113). In these cases the 
cleavage of the cytoplasm takes place in the normal manner and 
then there is the elongation of the daughter cells to form the 
characteristic ovoid cells. After the maturation of these cells, 
liberation of the young colony and its unrolling is wholly nor¬ 
mal. In other cases the cleavage and maturation of the cells 
takes place as usual, up to the time of the liberation of the 
young colony from the mother cell wall, but then there is no 
unrolling of the young colony but the four cells remain within 
the mother cell wall (Figs. 101, 102, 108, 110). Again, the 
whole mass of cells is liberated from the mother cell wall, but 
there is no unrolling of the colony but the four cells have the 
parallel nonconcurrent noncoplanar arrangement that is char¬ 
acteristic of I Tetradesmus (Figs. 101, 112, 115). Some colon¬ 
ies are surrounded by the old mother cell wall (Fig. 106) but 
usually the wall is lacking (Figs. 112 & 115). These colonies 
are not necessarily all in the same plane but one or more colon¬ 
ies may be at an angle to the others (Figs. 101 & 115). 
Many colonies remain attached to the mother cell wall after 
liberation. This may persist for two or three generations so 
that masses of cells are formed (Figs, 101 & 108). This 
formation of irregular cell masses, which is accompanied by a 
change in the shape of the cells from the ovoid to* the more 
