Henfrey, on some Fresh-water Algce. 
49 
Notes on some Fresh-water Confervoid Alg^, new to Bri- 
tain. Bj Arthur Henfrey, F.R.S., Professor of Botany, 
King's College, London. (Plate IV.) 
(Read March 26, 1856.) 
Pandorina Morum, Ehr; 
Pandorina, Ehrenberg {Char, emend). Frond a microscopic, 
ellipsoidal, gelatinous mass, containing imbedded near the 
periphery, sixteen or more biciliated, permanently active 
gonidia, arranged in several circles perpendicular to the long 
axis of the frond. The gonidia, almost globose, with a short, 
beak-like process, a red spot, and a pair of cilia which pro- 
ject through the substance of the frond to form locomotive 
organs upon its surface. Reproduction — 1, by the conversion 
of each gonidium into a new frond within the parent mass ; 
and 2, by the conversion of the gonidia into encysted resting 
spores, which are set free, and (?) subsequently germinate to 
produce new fronds. 
P. Aforum, Ehr. (PI. IV., figs. 1-25.) Fronds hyaline; from 
about 1-80" downwards. Gonidia either sixteen, and then 
arranged in four circles of 4, or thirty- two, and then in five 
circles, three at the poles of 4, and the intermediate three 
of 8 gonidia, which in the perfect form stand near the peri- 
phery and wide apart. In the forms which produce the 
resting spores, the gonidia are crowded together in the centre. 
The gonidia are green, but the contents of the resting spores, 
after they have become encysted, are converted into oily and 
granular matter of a bright-red colour. 
The description of Pandorina given by Ehrenberg, is so 
incorrect, that no one would be able to determine the organism 
by its aid ; but the figures in the ' Infusionsthierchen^ al- 
though rude, are sufficient for identification. Pandorina 
Morum has been observed by Focke* and Alex. Braunf in 
recent years, who pointed out the errors of Ehrenberg in 
stating that the gonidia had only one cilium and no eye-spot ; 
but we do not anywhere find a clear and satisfactory account 
of this creature. It was with much satisfaction that we re- 
ceived early in February of this year (1856), from H. Pol- 
lock, Esq., a bottle containing a vast quantity of Pandorina 
Morum, which he had found colouring the water in a pool at 
Hatton, near Hounslow, Middlesex. 
* * Physiolog.' Heft., ii. 1854, PI. IV. 
t * Verjungimg,' Ray Society's Vol. for 1853, pp. 169, 209. 
