ALGOLOGIOAL NOTES. 
87 
in length, which was spiral throughout all but the lowermost 
sixth. Fig. 1 represents this one- eighth its natural size. From 
near the base to a little below the first appearance of twist (la) 
only unilocular sporangia were found. Then a few plurilocular 
intermixed with unilocular ( a-b ). When spirality became marked 
( b-c ) the proportions were reversed, and in the uppermost third of 
the plant ( c-d ) the plurilocular became more numerous and the 
unilocular absent. In short, the plurilocular were proportionately 
numerous as the spirals became closer. 
The surface view of the projecting part of a spiral shows some 
of these bodies disposed in small groups, others scattered, or 
with a tendency to a linear arrangement in the direction of 
the spiral. The outline is subquadrate, and usually the cru- 
ciate appearance is manifest even early in the development of 
the upper portion of the assimilation cell into a sporangium 
(Fig. 2). 
In these spiral plants it is, of course, impossible to obtain a 
circular section. Fig. 3 shows a section of a spiral which is itself 
composed of several minor ridges and furrows, and it is especially 
on the most projecting portions that the plurilocular sporangia are 
most numerous. In the lower part of the figure with a circular 
outline they are almost, if not quite, absent, and here (as already 
indicated), in the portion of the plant where the spirals are looser, 
the unilocular may be present. It is also curious to note that in 
such a section the internal parenchyma of long cells may be 
shown in all aspects, transverse, longitudinal, and intervening 
diagonal. 
The assimilation cells destined to form plurilocular sporangia 
become swollen at the upper end, and granules form therein ; very 
early they exhibit a kind of cruciate parting when seen from above 
(Fig. 2). As the enlargement becomes more globose a partition 
is formed below (Fig. 4 b), and the pedicel thus produced becomes 
shorter as maturity is approached. When quite mature the 
breadth of sporangium is 35-40 fju. These bodies then form a 
striking contrast to the delicate greenish unilocular sporangia 
(Fig. 4a). The compartments are about 4 fi in width. When 
empty the longitudinal divisions are readily seen, with traces of the 
transverse ones (Fig. 4e), but owing to the pressure on all sides 
the empty sporangia soon disappear. The zoospores appear to be 
discharged from an opening in each quarter. I am unable to say 
from actual observation if they perform the role of gametes. I do 
not recall any hitherto known plurilocular sporangium that 
resembles this curious form. 
The spiral twist is evidently the result of a local production of 
the plurilocular sporangia induced, possibly, by exposure to sun- 
shine on one side more than the other. (I found these specimens 
in shallow pools exposed to such an influence, where the plants 
were prone for hours with water constantly flowing over them.) 
