214 CURREY, ON FRESH-WATER ALG. 
ture of its coat, there are some other points of structure in 
Pandorina requiring further examination and elucidation. 
Ehrenberg stated that the gonidia of Pandorina have one 
cilium, and no eye-spot, a view adopted by Fresenius, in the 
paper I have alluded to. Focke and Dr. Braun considered 
Ehrenberg’s observations inaccurate, and Mr. Henfrey agrees 
with them. As far as my observations go, I should say that 
the gonidia have usually two cilia, but that they frequently 
have no eye-spot. Mr. Henfrey has never been able to observe 
a pulsating vacuole, nor was any such vacuole visible in my 
specimens. Dr. Fresenius, on the other hand, has observed 
one, sometimes two, such vacuoles; and he remarks, that 
cilia and red spots are subject to considerable variation, and 
suggests that Stephanosphera and Volvox are probably the 
only distinct forms to be met with in the Volvocinee. I 
should protest against including Goniwm pectorale in the 
same genus as Stephanosphera; but, with this exception, 
Dr. Fresenius’s suggestion is probably correct. If, however, 
Stephanosphera and Pandorina are only forms of the same 
plant, the generic name ‘ Stephanosphera’. must give place to 
‘Pandorina,’ the latter bemg of much earlier date. 
A reference to Mr. Henfrey’s figures will show how much 
variety exists in different specimens of Pandorina. In figs. 
11—17 I have drawn several forms, all probably referable 
to Pandorina, which came under my own observation. Fig. 
12 is a large globe, filled with encysted berry-like masses, 
the membrane standing out a considerable distance from the 
gonidia. ‘This form was not in motion, although the cilia of 
the internal fronds (some of which are, from the size of the 
object, out of focus) were most clearly perceptible. Fig. 16 
shows a similar but much smaller frond, in which the cilia 
were not visible. Fig. 15, a frond in which only one ailium 
was apparent, but I cannot state positively that two did not 
exist. 
5. Monostroma roseum, n. sp.—This Alga, a species not 
hitherto described, seems to unite the characters of a Mono- 
stroma and a Palmella. It is to be found, usually in some 
quantity, in a stagnant pool at the conduit-head in the fields 
between Eltham, in Kent, and Halfway Street, and I have 
met with isolated specimens in two other pools near Shooter’s 
Hill. All three of these pools are lined at the bottom with 
particularly fetid black mud, but the water itself is clear. 
The fronds are of a bright pink, or sometimes lilac colour, 
and consist in their early stage of a hollow globular mem- 
brane, formed of closely approximated cells. Figs. 18 and 
19 represent two young fronds magnified fifty diameters ; 
