366 BOTANICAL GAZETTE [aay 
cells developing in opposite directions into filaments, while the 
two central cells protrude laterally and give rise to two more 
filaments (figs. to-12). Any cell of any of these filaments seems 
capable of producing a branch, and by the continued growth and 
branching the large complexes are formed, radiating from the two 
original cells at the center. Early in their history, however, 
division occurs in these cells in all three directions of space, so 
that a parenchymatous mass is formed, from which the branches 
radiate (figs. 13,14). CrENKOWSKI (2), in writing of Stigeoclonium, 
refers to a similar structure from which the branches radiate, and 
calls it a sole. 
As the age of a culture increases, papecially: in cultures of high 
concentration, the tendency toward the formation of these paren- 
chymatous masses increases until we find large solid structures 
with but little resemblance to a filamentous alga (fig. 16). 
It has long been known that in the Conjugatae certain forms 
of desmids resemble closely a single cell of corresponding filamen- 
tous forms, as, for example, Spirotaenia and Spirogyra; Cylindro- 
cystis and Zygnema; Mesotaenium and Mougeotia. A like simi- 
larity must be taken into account in the case of Conferva and 
Botrydiopsis, as the nature of the individual cells and the repro- 
duction are almost identical. In this new genus it would seem 
that we have a transitional form between the well defined filament 
of Conferva on one side and the unicellular Botrydiopsis on the 
other. Or possibly Conferva might be an intermediate form 
between this and Botrydiopsis, as certainly the branched nature 
would indicate a higher development than the single filament. 
But the filament of Conferva is less fragile than the filament of 
this form, so it is difficult to say what would be the most correct 
classification. 
Luruer (5) and West (6) would place all algae characterized 
by the distinctive light green shade shown in this form into 
one class, the HETEROKONTAE, irrespective of their shape, size, 
filamentous or unicellular nature; but whether one accepts the 
views of these writers or retains the older classification, the genus 
Aeronema must be placed near to Conferva or Bumilleria. 
