7 2 
i Bristol. — On the Alga-Flora of some Desiccated 
A second form (Text-fig. 10 , 5 and 6 ) had more linear valves with 
abruptly tapering rounded apices, and was about 14 to 15 ju, in length 
by 3 n in breadth. There were 15 to 1 6 carinal points in ,10 /ot and the 
striations were too indistinct to be determined. 
Both of these forms differ in the number of carinal points from that 
originally described for the species, but the agreement is so close in other 
respects that it seems advisable to regard them merely as variable forms of 
the same species. No previous record has been made of its occurrence in 
the British Islands. 
Chlorophycae. 
1. Chlamydomonas communis , Snow (Text-fig. 11 , 1 -7). 
A species of Chlamydomonas was found in the cultures of five of the 
soil-samples which agreed very closely with C. comimmis , Snow. This 
species, which has not previously been recorded for this country, was 
regarded by Snow as a plankton-species, but the characters of the form seen 
in the cultures resemble those of Snow’s species so closely that it seems 
probable that the species has a wider distribution than has previously been 
thought. The adult motile cells were subcylindrical or oval with a pointed 
anterior end, 11-5 to 13^ long and 6 to 7 yot broad, with a thin wall and 
a continuous bell-shaped chloroplast often raised into more or less 
prominent cushion-shaped lobes ; there was a single large pyrenoid in the 
centre of the cell. The pigment-spot was inconspicuous and near the 
anterior end of the cell. Zoogonidia, 4*5 n broad by 9 fx long, were formed 
by the longitudinal fission of the mother-cell contents into four parts, and 
were identical in structure with the adult cells. Very rarely a slightly 
oblique fission was observed (Text-fig. 11 , 7), but in this case both planes 
of fission were parallel to the same axis of the cell. 
2. Chlamydomonas pluristigma, n. sp. (Text-fig. 11 , 8-14). 
This species was found in a single soil only, but its characters differed 
considerably from those of any previously described species. The adult 
cells were oval, with usually a pointed anterior end ; they were 13 to 1 6 yut 
long by 9*5 to 11 j ul broad and possessed a comparatively thick cell-wall. 
The chloroplast was bell-shaped and lined practically the whole cell-wall 
except at the anterior end, but it was occasionally perforated (Text-fig. 11 7 
9 and 10) and the inner surface was frequently raised into cushion-shaped 
lobes. There was a single large pyrenoid near the centre of the cell, and 
two or three pigment-spots variously disposed in the cell, one near the 
anterior end being much larger than the rest. Zoogonidia, 7 /x broad by 12 n 
long, were formed by one oblique and one transverse division of the contents, 
and were similar to the adult cells. 
The following is a diagnosis of the species : Zoogonidiorum tegumentum 
satis crassum, apice in papillam hyalinam provectum. Celiulae ovales vel 
