THE YAN YEAN RESERVOIR, VICTORIA. 49 
Hab. Among weeds, Honeysuckle Flat, and in small pools, Ottelia Creek 
(Sept. 3, 1907). 
This interesting member of the Ulotrichaceæ has been previously found in 
Germany, the United States, and Paraguay. The Australian forms agree 
with those described as Radiojilum apiculatum in the presence of a slight 
apiculus at each side of the cell, but the cells themselves are proportionately 
longer. R. apiculatum must now be regarded as identical with R. conjunc- 
tivum, since Schmidle has re-examined his specimens of the latter and 
found that he omitted some of the most salient characters from his original 
description—characters upon which the species A. apiculatum was founded 
(vide Schmidle, in Botan. Zeitschr. (1900) по 12). 
The wall of each individual cell is composed of two halves, and cell- 
division appears to take place much as it does in some of the sim pler types of 
Desmids, such as Penium, by the interpolation of two new half-cells between 
the old ones. The line of junction of the old and new halves of the wall is 
distinctly visible in most specimens, and is particularly obvious at the 
marginal apiculations, the latter owing their prominence to the projecting 
suture at this region. Each fully-grown half is helmet-shaped, but in its 
earliest stages the young half is much flattened. The chloroplasts are parietal 
and cup-shaped, occupying about two-thirds of the interior of the cell-wall. 
They are disposed very largely back to back in pairs of adjacent cells, The 
connections between the cells are not mucilaginous, but are caused by polar 
thickenings of the cell-wall. In the apical cell of a filament the terminal, 
free half of the cell is hemispherical. 
One filament was observed which possessed a lateral branch (PI. 6. fig. 3), 
the basal cell of the branch being attached by a forked polar connection to 
two cells of the main filament. This branch most likely arose as a result of 
rapid cell-division, the middle cell of three sliding out laterally and deve- 
loping a connection with each of the other two. 
Mobius has described (in Abhandl. d. Senckenb. naturf, Ges. xviii. (1894) 
p. 320, t. 1. figs. 22-25) from Queensland an Alen which he placed as a 
variety of Ногтозрота transversalis, Bréb. ; but it appears probable from his 
description of the cell-division, that the plants he observed should be relegated 
to the genus Zadiofilum. In the two known species of the latter genus— 
R. conjunctivum (including В. apiculatum) and №. flavescens—no longitudinal 
division of the cells has been observed such as Móbius describes as occurring 
in his Queensland plants. Möbius considers that the genus Hormospora 
should have a place in the Tetrasporaceæ in proximity to Palmodactylon ; but, 
so far as I can judge from a wide knowledge of all these genera, there is no 
doubt whatever that both Zormospora and Radiofilum are feebly developed 
members of the Ulotrichacese. 
LINN. JOURN.—BOTANY, VOL. XXXIX. E 
