Lewis . — The Life History of Griffithsia Borneiiana . 671 
Griffithsia. 
Corallina. 
Polysiphonia. 
Resting nucleus : 
chromatin 
In large central 
granules 
In scattered granules 
of varying number 
In reticulum 
Resting nucleus : 
nucleolus 
Karyosome with some 
plasmosome substance 
Plasmosome 
Plasmosome 
Synapsis : 
chromosomes 
Broad irregular bands, 
free at ends 
? 
Double spirem 
Origin of 
chromosomes 
From central nucleo- 
lar bodies 
From scattered chro- 
matin granules 
Segmentation 
of spirem 
Fate of nucleolus 
Achromatic portion 
disappears at pro- 
phase or persists till 
telophase 
Disappears at 
prophase 
Disappears after 
prophase 
Daughter-nuclei 
Assume resting con- 
dition 
Assume resting con- 
dition 
Not organized 
Second mitosis 
In daughter-nuclei 
Inside membrane 
of mother-nucleus 
Nuclear mem- 
brane 
Disappears or pulls 
apart after metaphase 
of first division 
Disappears before 
metaphase of first 
division 
Persists through 
both divisions 
This comparison serves to emphasize one point particularly. At a 
critical stage in the life-history of rather closely related members [Polysi- 
phonia and Griffithsia) of a highly specialized group, the cytological 
phenomena are of a most varied nature. During the period of synapsis, 
and up to the time of the formation of the chromosomes, the cytological 
events in Polysiphonia are more like those in Lilium than those in 
Griffithsia or Corallina. The behaviour of the nucleus in the formation of 
the tetraspores in Griffithsia is much more similar to that in Corallina than 
to that in Polysiphonia , a more nearly related genus. The bearing of these 
facts is obvious ; cytological phenomena cannot be considered trustworthy 
guides to relationships. 
Tetraspore-like Structures on Sexual Plants. 
As stated above, one individual has been found which produced normal 
antheridia on the majority of its filaments, but which produced on a 
considerable number of filaments structures resembling the sori of tetra- 
spores. As this case is of considerable theoretical interest at the present 
time, I shall now give some of the details of the structure of this plant. 
The portion of the plant bearing antheridia was perfectly normal in 
appearance. The cells were of the usual size and shape, and bore antheridia 
of the normal type in abundance. The number of chromosomes appearing 
in mitoses in the antheridial filaments was found to be about seven (the 
reduced number, characteristic of the gametophyte). Mitosis has as yet 
