40 . ae a 
CLOSTERIUM, Nitsch. 
Fronds elongated, attenuated, more or less lunately curved or 
arcuate, entire, not constricted at the middle, the junction of the 
segments marked by a pale transverse band. Endochrome often 
arranged in longitudinal fillets, and at each extremity having a terminal 
clear space, in which are active granules ; empty frond smooth or with 
longitudinal striw, never granulated.—Archer, in Pritch. Inf.; Cooke’s — 
Brit. Desm., 17 
C. gracile, Bréb. Cooke’s Brit. Desm., 22. Frond very slender, 
about twenty-five to thirty times as long as broad, linear, nearly big | 
Cabtheortremitios: whcchare id 1s sid ends 
obtuse, endochrome arranged in a zigzag or sub-spiral manner. Empty — 
fronds without striew. Zygospore globose, smooth. Size: 0°15-0'2 mm. — 
x 5-6 w; 62-0°35 mm. x 8 » (C.); diam. 5-6. 
rof. Moebius says:—‘“ Besides the typical form ( 
8 
5-6 » broad, 133 p 
long) a still smaller form was observed, which wa ree ck 
sca 
slender, fifteen to even thirt 
. 
| 
C. juncidum, 2ai/s. Cooke’s British. Desmids, 30. Fronds very | 
: y-five times as long as broad, linear, — 
: | . 
a 
| 
jl 
D.); diam., 11-12 » (W.).—Cooke, Le. f 
Prof. Moebius says :—“ This species is very variable in the length 0 
ie cells ; I found them 11-16 » thick in the middle and 156-350 p 
ong. : 
Fig. 31: a, living cells ; b, empty cells; ¢, zygospore—Cooke, le. 
—— Burpengary, Thos. L. Bancroft. Also found in Europe, Asia, and : 
C. acerosum, (Schrank) Ehr. Cooke’s British Desmids, 20. 
Frond slen : : 
‘ ooth, placed between the dehiscing empty fran 
Size: 0°15-0 42 mm. xX 1-40 pe (R.) ; 0°35-0'°42 mm. Fs 2000 A (A.); a 
diam., 35-62 » (W.). a 
Prof. Moebius’ note is as follows :-—“ Rare, 52 » broad, 7 15 p longs 
cell-membrane smooth. Tn the latter respect statements vary: Ralls 
(brit. he strie are wanting, or are faint ; according a 
to Kirchner (Algw of Silesia), the cell-membrane is mostly distincl’y 4 
Toni (Sylloge), smooth or generally v7 
cies seems to occur everywhere, but ! ed by 
_ to Australia. To the localities mentioned by - 
aya.” ee 
ogc Se ire Thos. L. Bancroft. Also found in Evrope, Jap 
