Lewis . — The Life History of Grijfithsia Bornetianct. 669 
Vacuoles develop in the cytoplasm in the centre of the nucleo-kinoplasmic 
mass. At the same time, small chromatophores begin to appear in the 
cytoplasm along the outer border of the tetrasporangium. These increase 
in size, and a few extend along the partitions into the body of the proto- 
plast. In this condition the tetrasporangium remains for a long time, 
increasing in size and in vacuolization of the cytoplasm. The significance 
of this incomplete separation of the spores probably lies in the fact that 
food material seems to pass up through the basal cell. If the spores were 
completely separated before maturity, only one of the four would be in 
communication with the stalk cell, the source of supplies. However, 
inasmuch as the chromatophores at this stage are well developed, it seems 
probable that the tetrasporangium is capable of elaborating at least part of 
its food material for itself. 
Berthold ( 7 ) seems to have been the first to point out this incomplete 
separation of the tetraspores of red algae after the division of the nucleus 
of the mother-cell, though Schmitz ( 69 ) had given an account of two 
successive nuclear divisions in the tetraspore-mother-cell. 
The tetrasporic branches are from their inception surrounded by 
the swollen wall of the vegetative cell on which they are borne. A portion 
of this wall is carried out by the developing tetrasporic cells. As the cells 
develop, the portion of the wall surrounding them swells greatly and 
appears to become gelatinized, ceasing to respond to the tests for cellulose. 
The tetrasporangium, with the incompletely separated spores, increases 
markedly in size. The nuclei also enlarge and show abundant chromatin, 
in the form of the 12-14 masses already mentioned. Each mass is 
differentiated into lightly and darkly staining areas. Not infrequently the 
number of these masses is greater than this, as many as twenty having 
been counted in some cases ; and sometimes the number is considerably 
less than twelve. This variability in the number of chromatin masses in the 
resting nucleus serves to show that they do not have the same constancy in 
numbers that the chromosomes show, and therefore are not to be relied on 
as an index of the condition of the nucleus, whether haploid or diploid. 
As the tetrasporangium enlarges, the cytoplasm becomes more coarsely 
vacuolate, and the vacuoles in the central protoplasmic mass become con- 
spicuous. The partitions now grow in until they meet in the centre of the 
tetrasporangium, their ingrowth being apparently aided by the position of 
the large central vacuoles already mentioned (Fig. 131). The spores are 
now completely separated, with the nuclei in the inner corners. The nuclei 
wander toward the centre of the spores, the chromatophores at the same 
time migrating so as to line the entire periphery, and the spores round off, 
becoming oval in shape (Fig. 132). The lowest spore, up to this time 
attached to the stalk-cell by a slender thread of cytoplasm, breaks away at 
the point of attachment, and the strand is withdrawn into the body of the 
