which are blunt, rounded ; membrane smooth and colourless.
Endochrome a single longitudinal band, not plicated ; each
loculus containing usually a single moving granule, forming a
rounded cavity in the plasma, at some distance from the apex.
Siz e.
Ireland.
C lo s te r ium D ian® . Ehr. Infus. (1838), t. 5 ,/ . 17.
Frond slender, six or eight times as long as broad, crescentshaped,
much curved, rapidly attenuated, upper margin very
convex, lower very concave without a central inflation, ends
snb-acnte, with a very slight emargination a t the upper outward
ex trem ity ; large granules in a single series ; empty
frond somewhat straw-coloured, or faintly reddish, without
stri® suture evident. Zygospore globose, smooth.
S iz e . 0T7 mm. x 20 (R .) ; O-H-0'3 mm. x 10-25 p
(D.) ; diam. 16-20 p (W.) ; zygospore 36 p (L.).
Ralfs. Desm. (1848), p. 168, t. 28, f. 5. Archer in Prit.
Inf. (1861), p. 748. Wolle Desm. U.S. 44, t. 7, f. 8-9, t. 8,
f. 4. Hassall Fr. Alg. (1845), p. 371. Delponte Desm.
(1878), p. 99, t. 17, f. 45-61. Nordstedt Desm. Ai’ot. (1875),
p. 15. Nordstedt Norges Desm. (1873), p. 42. Cleve Sver.
Desm. (1864), p. 494. Lundell Desm. Snec. (1871), p. 81.
Nordstedt Desm. Arct. (1875), 37-39. Grunow Desm.
Austr. (1858), p. 497. Wood F. Wate r Alg® U.S. (1872),
p. 114. Wittrock Scan. Desm. (1869), p. 22. Brebisson
Liste Desm. (1856), p. 149. Rabh. Alg. Eur. (1868), p. 133.
Wille Nov. Sem. (1879), p. 59. Jacobsen Desm. Denm.
(1874), p. 170. Nordstedt Desm. Spitz. (1872), p. 26.
Glosterium Venus, Kutz. Phy. Genu. (1845), 130. P e tit
Liste Desm. Paris (1877), p. 28.
Olosterium acuminatum, Kutz. Phy. Germ. (1845), 130.
Glosterium ruficeps, Ehr. Abh. Berl. Ak. (1831), p. 67.
Closterium Diance a. typicum, Klebs. Desm. Pruss. (1879),
p. 11.
H ab. In quiet water.
Sussex, Cheshire, Westmoreland, Wales, Scotland; France,
Germany, Ita ly , Sweden, Norway, Denmark, Austria, Spitzbergen,
Nova Zembla, Russian Lapland, United States.
Plate X I I I . , fig. 3. a, living c e ll; h, empty cell.
I I Fronds gradually tapering, curvature often gradual, lower
margin concave, inclined downwards at the rounded truncate,
or nearly acute ends. Fmpty frond striate.
t Fronds crescent shaped.
C lo s te r ium c y n th i a . Not. Lesm. Ita l. (1867), p . 65, t. 7, / . 71.
Fronds ten times as long as broad, elongated, fusiform.
gradually attenuated from th e middle towards each extremity,
apices obtuse, elegantly arcuate, almost a semicircle.
Endoohrome dense, in terrupted in th e middle of the
frond. Terminal space occupied by a single active grannie,
membrane amber colour, delicately striate witb 1-3 tra n s verse
stri® a t the middle. Stri® of th e membrane about 10
or 12. Zygospore globose, smooth.
S iz e. 104-160 x 11-18 p ; zygospore 28-31 p (L.).
Archer Micr. Journ. (1868), viii., p. 118. Lundell Desm.
Suec. (1871), p. 78. Nordstedt Norges Desm. (1873), p. 40.
Jacobsen Desm. Denm. (1874), p. 176.
Closterium Archerianum c. Cynthia, Klebs. Desm. Pruss.
(1879), p. 13.
H ab. In turbaries.
Ireland, Sweden, Norway, Denmark, Italy.
Plate X I I I . , fig. 2. a, living c e ll; h, empty cell.
In Bome respects C. cynthia resembles C. Jenneri, but it is a larger
species. I t is marked by having a solitary, somewhat large granule iu
the middle of the terminal space, not a cluster of small ones. “ It at
once catches the eye by its peculiar curvature, differing from that of the
much-cnrved forms at all liable to be mistaken for it. I t is not so
equally arched, and the ends are more rounded and blnnt than in them ;
in fact it is not so graceful a form as C. Leibleinii or C. Liance, which it
seems most to approach in size. From all these it differs in being
striolate.”
C lo s tex ium A x c h e x ia n um . Cleve in Lundell Lesm. Suec. p. 77,
t. 5, / . 13. •
Narrowly lanceolate, ten times longer than broad, equally
curved, semilunar or semicircular, ventral side not swollen,
somewhat obtuse a t each apex, more or less extended,
equally attenuated, 2-4 stri® transversely in th e centre,
membrane yellow, becoming brownish, longitndinally striate,
with about 10 stri®, amylaceous granules disposed in a single
series.
S iz e . 196-230 x 18-21 /x (L.).
Archer Micr. Jonrn. xiii. (1873), p. 213. Nordstedt Norges
Desm. (1873), p. 40. Jacobsen Desm. Denm. (1874), p, 175.
Closterium Archerianum a. typicum, Klebs. Desm. Pruss.
(1879), p. 13.
N. Wales, Ireland, Norway, Denmark, Germany.
Plate X I I I . , fig. 5. a, living c e ll; b, empty cell.
C lo s tex ium c a lo s p o ium . W ittr. Antéele. (1869), y). 2 3 ,/. II.
Small, semilunate, not swollen in th e middle, slender, 6 to
9 times as long as broad, acuminate a t th e apices, vesicles in