On a Species of Chlamydomonas (C. sphagnicola, 
F. E. Fritsch and Takeda — Isococcus sphagnicolus, 
F. E. Fritsch)* 
BY 
F. E. FRITSCH 
AND 
H. TAKEDA. 
With fourteen Figures in the Text. 
I N the first of the ‘Notes on British Flagellates’, 1 published by one of us, 
a new genus of green Flagellates was described under the name ot 
Isococcus. A further examination of more abundant material, collected in 
May of last year and since kept in the laboratory, has shown that there 
were certain errors in the original description of this organism. Moreover, 
the facts that have come to light and are detailed below indicate that the 
organism in question does not constitute a distinct genus, but is a somewhat 
peculiar species of Chlamydomonas , which must pass under the name of 
C. sphagnicola. Whilst the material upon which the new observations were 
made was collected from the same marsh at Keston (Kent) from which the 
organism was first obtained, it may be mentioned that this species of 
Chlamydomonas has since been discovered also in one of the ponds in 
Richmond Park (Surrey). 
The motile individual of C. sphagnicola is rather variable in shape. 
As a rule it is broadly ellipsoid (Figs. 1-3) ; not rarely, however, it is 
ellipsoid or oblong-ellipsoid, with more or less pointed or rounded poles 
(cf. Figs. 5, 8, 9, 10, 12), whilst in a few cases the individuals are subglobose 
or even globose (Fig. 6). When viewed from the anterior or posterior end 
the organism is circular (cf. Fritsch, loc. cit., Fig. 1, D and G), but if front 
and side views of the same individual are compared (Figs. 7-9, 13) they are 
seen to show slight differences in shape. The length (excluding the 
papillae) varies between 15 /1 and 27 //, the breadth between 9 (jl and 22 
(up to 25 fj. broad according to the old description, loc. cit., p. 341). The 
cell-wall is remarkably thick, and consists of an outer firmer portion and 
a usually well-developed inner gelatinous portion (sometimes as much as 
4 tx thick) which, in the previous description (loc. cit., p. 341), was regarded 
1 New Phytologist, vol. xiii, 1914, pp. 34 1-6. 
[Annals of Botany, Vol. XXX. No. CXIX. July, 1916.] 
