196 
S. tenuissima (Hass.), Ktz. Spec. Alg., 437. Temperate house 
pools; interminglel with Sp. porticalis, July, 1902. Zygospores 
not observed. 
Zygnema, Kiitz., 1843. 
Z. pectinatum, Ag Syst., 78, n. 8. Moat, May, 1902; water- 
lily pond, June, 1902. Zygospores not observed. 
*Z. stellinum ee ) Ag. Syst., 77, n. 4. Locality and date 
unknown (Wrigh 
3. DESMIDIACEAE, 
Gonatozygon, De Bary, 1856. 
G. Brebissonii, De Bary Conj., 11, t. 4, f. 26, 27. Lake, July, 
1902 (isolated). 
Docidium, Br¢b., 1846. 
*D. clava Kütz. in Ralfs Desm. (1848), 156, t. 26, 7. 
ep. "fedis in soceri ‘of Royal Microscop. Society, 1891, S Té (x 
pe Nitzsch, 1817. 
unula (Miller), Ehrb. Abh., 1830. Laboratory tank, July, 
is (Wright i plankton of pond, April, 1892 (Chodat !) ; dios 
May, 1902 hi). 
Es acerosum, Erb. Symb. Phys. Phyt., t. ii., f. 9. Plankton of 
pond and Thames, 1902; laboratory tank, May, 1902 ; temperate 
house pools, July, 1902. 
(m 
C. Ehrenbergii, Meneg. Syn. Desm., 232. Isolated amongst other 
Algae in side tanks of water-lily house ( (15), April, 1902 ; temperate 
house pools, June, 1902 ; streamlet in rockery, September, 1902, 
Var. rubro-striolatum, nov. var. Frond elongated; dorsal 
surface strongly convex, ventral slightly concave with am 
or less conspicuous central i nflation ; considerably attenuated 
towardsthe eee ends. Large granules irregularly dar om 
E. 
in considerable number in each half of the cell. 
reddish, analy distinctly striolate, striae pps 
aem distinguisha e from one another; a conspicuous central 
potire dari nt. Zygo ospore not observed. Breadth des 
1005; length about 500 p. Temperate house pools, amongst 
Ulo Aoi, July, 1902; streamlet in rockery, Boptatbor, 1902. 
C. moniliferum, Erb. Inf., 91, t. 5, 4 16. Plankton of Thames, 
August-September, 1902 ; moat, July, 1 902. 
C. Jenneri, Ralfs Desm., 107, t. 28, f. 6. Lake, June, 1902. 
*C. Leibleinii, Kiitz. Syn. Diat., 596. cp. Dennett in Journal of 
Royal Microscopical Society, 1897, 511 (!). 
C. bass. Ehr. Infus., 92, t. 5, f. 17. Lake, May, 1902. 
tum, Corda Alm. eS 9, f. 61--63. Lake, July 
1897. 7 Wright D. 
