300 Johnson. — Sphaerococcus. coronopifolhis , Stackh . 
auxiliary cell which is the mother-cell of the carpogenous 
branch and bears in addition a cell-complex, fuses with the 
carpogonium, and with the nearest cells of the cell-complex, 
giving a large multinucleate cell from which sporigerous fila- 
ments sprout out. In Sphaerococcus there is a combination 
of the three chief types of fruit-formation of the Florideae ; 
for the ooblastema-threads arising from the surface of the 
carpogonium are comparable to the sporigerous filaments of 
the Helminthocladieae (Nemalion, Batrachospermum , etc.), and 
those from the surface of the fused auxiliary cells and from 
the carpogenous cells (secondary auxiliary cells) are com- 
parable to the sporigerous filaments of the Rhodomeleae 
and other Florideae with more or less compact thallus, and 
to the sporigerous filaments (meta-ooblastema-threads) of the 
Squamarieae and Cryptonemiaceae. A comparison of the 
course of development of the fruit in Sphaerococcus with that 
in Gracilaria will show how very similar these two genera 
are in this respect. Comparison of the vegetative thallus 
of the two shows Sphaerococcus to be the less modified form. 
In Gracilaria the central axis of the thallus branch is no 
longer evident, since its lateral branches are as well-developed 
and have applied themselves closely together and to its sides, 
forming a central medulla of large cells in which the joint- 
cell of the central axis is obscured. The absence of a clearly 
marked central axis in 5. australis Harv. caused Harvey 1 
to exclude this plant from the genus Sphaerococcus and to 
place it nearer Gracilaria . Opinions differ as to the other 
genera to be included in the Sphaerococcaceae. Schmitz 2 
considers Nitophyllum to be a member of the family and 
describes its procarpia as being the simplest. Its thallus is 
very different from that of either Sphaerococcus or Gracilaria , 
and its fruit, judging from the brief account of Schmitz, is not 
at all like that which I have described in these two genera. 
Hauck 3 considers Chondrymenia to be the third genus of 
1 Harvey, op. cit. 
3 Schmitz, op. cit., p. 24. 
3 Hauck, Rabenhorst’s Krypt.-Flora, Die Meeresalgen, 1885, p. 184. 
