Lewis . — The Life History of Griffithsia Bornetiana. 675 
The description given above applies to the majority of sporelings 
examined. Many sporelings, however, show variations from the type 
described. For instance, it happens rather frequently that cell-division 
occurs after the formation of only four nuclei (Fig. 145) and before the 
sporeling assumes the elongated shape represented in Fig. 144. 
The 3-celled stage is first attained in about twelve hours from the time 
the spore is shed. It persists, under laboratory conditions, for several days, 
during which time the three cells change greatly in size, shape, and appear- 
ance. The most striking changes occur from the second to the third day 
after the spores are shed. The cells increase greatly in size, and a large 
central vacuole is formed in each. The protoplasm and inclusions being 
spread over a larger area form a thin film, in which the chromatophores are 
no longer crowded, but are separated by considerable clear spaces ; the 
sporeling therefore becomes lighter in colour and more transparent. The 
following comparison of sporelings of the second with those of the third day 
gives some idea of the great increase in the size of the cells. 
Length in mm. 
Diameter in mm. 
Second day 
Third day 
Second day 
Third day 
Apical cell 
*°37 
•133 
•067 
•073 
Middle cell 
•037 
.467 
•067 
• i 
Basal cell 
.047 
• 107 
.04 
•073 
Total 
.121 
• 7°7 
The number of nuclei in the cells, even after enlargement, is small. 
Several counts indicated that there are in the apical cell on an average 
25-30 nuclei, in the middle cell 20-25, in the basal cell 5-10. These nuclei 
in the resting condition are very small, averaging, perhaps, 1 fx in diameter. 
In structure they resemble the nuclei of the older vegetative cells. 
The changes in the apical and middle cells consist mainly of (1) a great 
increase in length, (2) slight increase in breadth, and (3) the distribution of 
the protoplasm and inclusions over a much larger area. 
In the basal cell, besides an increase in size, the most striking changes 
are those of shape. These changes depend to a large degree on the sub- 
stratum. In case the sporeling is attached to some soft body, such as 
another alga, the basal cell remains somewhat top-shaped, with the pointed 
end applied to, or in some cases wedged into the substratum (Figs. 148, 
149, 152, 153). If, however, the sporeling is attached to a hard body, such 
as glass or stone, the basal cell becomes greatly elongated, in some cases 
coming to equal in length all the rest of the sporeling (Figs. 150, 151). 
When this occurs, the basal cell resembles strikingly a rhizoid of the older 
plant. 
Z z 
