transverse view broadly elliptic. Zygospore orbicular formed
■within one of the two conjugating joints, the endochrome
passing over from one by a narrow connecting tube produced
between the otherwise but little altered broken-iip single joints.
Siz e . 60-80 p broad (K.) ; 25 X 46 (D.) ; 37 X 40 (E.).
Kirchner Alg. Schles. (1878), p. 132. Wolle. Desm. U.S.
(1884), t. iii., f. 1-4. Jacobsen Desm. Denm. (1874), p. 214.
Lundell Desm. Suec. (1871), p. 95. Wittrock Scan. Desm.
(1869), p. 24. Nordstedt Norges Desm. (1873), p. 49. Hass.
Fr. Alg. (1845), p. 342,t. 83,f. 1. Cleve Sver. Desm. (1864),
p. 496.
Arthodesinus t cylindricus, Ehr. Inf. (1838), p. 1838.
Hyalotheca cylitidrica, Ehr. Kurze. Nach. (1840).
Desmidium compressum, Corda Aim. Carls. (1840), p. 18.
Didymopriim cylindricum, Ealfs. Ann. N. Hist. (1845'), xvi.
p. 10.
Didymoprium Orevillei, Kutz. Phyc. Gen. (1843), p. 166.
Ealfs. Desm. (1848), p. 57, t. 2. Ralfs. Brit. Alg® No. 24.
Archer Prit. Inf. (1861), 723. Delponte Desm. (1876), p.
64, t. i., f. 20-28. Petit Liste Desm. Paris (1877), p. 30.
Wood F. Water Alg® U.S. (1872), p. 125. Breb. Liste
Desm. (1856), p. 11«. Notaris Desm. Ital. (1867), p. 27, t.
i., f. 3. Rabh. Alg. Eur. (1868), iii., p. 153,
H ab. In ponds.
Sussex, Surrey, Hants, Lancashire, Cornwall, Wales, Scotland;
France, Germany, Italy, Sweden, Norway, Denmark,
United States.
Flaie IV ., fig 2. a h, living cells; c, empty cells; d, transverse view;
e, zygospore.
D e sm id ium S w a itz ii. (A g ) Ralfs. Desm.^ t. 4.
Filament triangular, equal, with a single longitudinal dark
waved line formed by the third angle ; joints in front view
somewhat quadrangular, broader'than long, with two slightly
angular crenatures on each lateral margin, united at the whole
of their end margins by a thickened border, end view trangular,
endochrome three-rayed. Zygospore oval.
S iz e . Diam. 37 p (R.) ; 36 u (W .) ; 24-27 u (K . ) ;
21-36x25-50 (D.).
Wolle. Desm. U.S., (1884), t. ii., f. 1-6. Agardh. Syst.
(1824), p. 9. Ealfs. Desm. (1848), p. 61, t. 4. Ralfs. Brit.
Alg® No. 26. Archer in Prit. Inf. (1861), p. 723. Harv.
Man., 196., Grev. S. Or. FI. t. 292. Ehr. Inf., p. 140, 1 .10, f.
8. Hass. Fr. Alg, (1845), p. 344, t. 83, f. 7. Delponte Desm.
(1876), p. 68, t. 2, f. 8-20. Cleve Sver. Desm. (1864), p. 496.
Lundell Desm. Suec. (1871), p. 95. Nordstedt Norges Desm.
(1873), p. 49. Petit Liste Desm. Paris (1877), p. 30.
Grunow Desm. Austr. (1858), p. 498. Wood F. Water
Alg® U.S. (1872), p. 126. Wittrook Scan. Desm. (1869), p.
25. Brebisson Liste Desm. (1856), p. 119. Notaris Desm.
Ital. (1869), p. 28, t. i., f. 4. Rabh. Alg. Eur. (1868), p. 154.
Jacobsen Desm. Denm. (1874), p. 214. Kirchner Alg. Schles.
(1878), p. 132.
Diatoma Swartzii, Agardh. Disp. Alg. (1811).
H ab. In shallow pools.
Generally distributed in England, Wales, Scotland, Ireland;
France, Germany, Sweden, Denmark, Norway, Austria, Italy,
United States.
Plate V., fig. 2. a, living cells; I, empty cells; c, zygospores ; d,
transverse view.
D e sm id ium q u a d r a n g u la tum . Ralfs. Desm., t. 5.
Filament quadrangular, varying in breadth from its twisting,
having two longitudinal waved lines; joints in front view
broader than long, with two somewhat rounded crenatures _ on
each lateral margin, united by the whole of their end margins,
end view quadrangular ; endoohrome four-rayed.
S iz e . Diam. 50-60 p (W.) ; 2 4 x 5 7 p (D.) ; 55 p (R.).
Wolle. Desm. U.S., t. ii., f. 13, 14. Rabh. Alg. Eur. (1868),
iii., 165. Ralfs. Ann. Nat. Hist. (1845), XV., 1 .12, f. 9. Archer
Prit. Inf. (1861), 723, t. 2, f. 37-40. Ralfs. Desm. (1848), p.
62, t. 5. Ralfs. Brit. Alg. No. 27. Delponte Desm. (1876),
p. 72, t. 2, f. 21-27. Wood F. Water Alg® U.S. (1872), p.
126. Brebisson Liste Desm. (1856), p. 301.
Desmidium quadrangulare, Kutz. Phy. Germ. (1855), p. 111.
H ab. In boggy pools.
Cornwall, Westmoreland, Wales, Scotland; France, Germany,
Italy, United States.
Plate V., fig. 3. a, living cells; h, empty cells ; c, transverse views.
D e sm id ium a p to g o n ium . Brel. A lg. Fal. 65, t. 2.
Joints quadrangular in front view, broader than long, with
two rounded crenatures on each lateral margin, united at the
outer portion only of each end margin by mutual projections,
thus producing intervening central oval foramina.
S iz e . Diam. 25-38 p (W.) ; 22-87 p (K.).
Breb. Alg. Fal. p. 65, f. 2 (1885). Wolle Desm. U.S. (1884),
t. ii., f. 6, 7, t. xlix,, f. 7. Archer Prit. Inf. (1861), p. 723, t.
8, f. 7, 8. Cleve Sver. Desm. (1864), p. 496. Lundell Desm.
Suec. (1871), 95. Nordstedt Norges Desm. (1878), p. 50.
Petit Liste Desm. Paris (1877), p. 30. Wood F. Water
Alg® U.S. (1872), p. 126. Wittrook Scan, Desm. (1869), p.
25. Rabh. Alg. Fur. (1868), p. 154. Jacobsen Desm. Denm.
(1874), p. 214. Kirchner Alg. Schles. (1878), p. 132.