426 SIR RAY LANKESTER. 
my friend Prof. Hickson, F.R.S., of the University of 
Manchester. I was at first unable to identify it, but sus- 
pected it to be the Botryococcus of Kiitzing (1849), a 
suspicion which I was unable to confirm owing to the fact 
that no good figures of it were published. In 1896, however, 
Prof. Chodat published a coloured plate (Pl. III, p. 333) in 
Morot’s ‘ Journal de Botanique’ (which only came to my know- 
ledge last year) accompanying a full account of the Botryo- 
coccus Braunti of Kiitzing, which he found abundantly 
and at various seasons of the year on certain parts of the 
surface of the Lake of Geneva. Prof. Chodat describes, and 
his figures illustrate, a purely green form of this organism, a 
phase which I have not seen. But he mentions that fre- — 
quently the Botryococcus develops a brick-red coloured oil, 
which may be more or less abundant, and give a completely 
red appearance to the floating colonies. He points out that 
the red oily matter enables the organism to float, and ex- 
presses some doubt and interest as to the exact mode of 
formation of this red-coloured oil. 
Whilst referring the reader to Prof. Chodat’s memoir 
for many interesting observations, I will now briefly describe 
my own observations and the drawings made by me nearly 
twenty-five years ago, which I have never published, but now 
reproduce in Pl. 25 accompanying this paper. 
General form and colour of the fronds.—The little 
“orains’? of Botryococcus which float practically on the 
surface of the water in which it occurs are irregular, incom- 
plete, hollow, spherical, or kidney-like bodies, connected one 
to another by growth and origin, and separating by rupture 
from one another after a certain size and shape has been 
attained. A group of these growths magnified about one 
hundred diameters is shown in outline in Pl. 25, fig. 4. In 
fig. 1 of Pl. 25 a smaller frond is shown more highly magni- 
fied. This drawing also serves to show the very striking 
coloration of the first specimens which came under my 
notice, viz. a golden-red mass with a translucent green- 
coloured cortex. The colouring is so strong as to recall the 
