ZYGNEMACE. 95 
form a major. 
Diameter of threads ‘05 mm. Bands 2 to 3. 
. form 8 minor. 
Diameter of threads 032 mm. Band single. 
Sizz. Zygospore :078--096 x 045 mm. 
Archer in Quart. Journ. Micr. Sci., 1873, xiii. p. 486. Petit 
Spirogyra p. 11, 6. 2, fig. 11-13. 
Spirogyra protecta, Wood. F. W. Alg. t. 14, f. 3. 
In bogs and moor pools. 
Plate XXXVIII. fig. 2. a, sterile cells X 200; b, e, conjugating cells 
with zygospores X 200; d, outline zygospore X 400. 
B. Chlorophyll bands single. 
Spirogyra quadrata. (Hass.) Petit. 
Sterile cells 3 to 9 times aslong as broad. Fertile cells turgid, 
quadrate. Zygospore elliptical. Sporoderm brown. 
Sizz. Cells -024 to 027 mm. Zygospore *042-:048 mm. 
diam., 1} to 2 times as long. 
Petit Spirogyra p. 8, t. 1, fig. 138. Bull. Soc. Bot. France 
xxi. p. 14, t. 1, fig. 2. 
Zygnema quadratum, Hass. Alg. 157, t. 387, f. 1,2. Jenner 
Fl. Tunb. Wells, 182. 
Rhynchonema quadrata, Kutz. Tab. Phy. v. t. 32, f. 6. 
In pools. 
We have accepted Petit’s diagnosis of this species, which Hassall had 
seen only with the Rhynchonema mode of conjugation, but which has 
now been ascertained to conjugate in both ways. His description is very 
short for a species which he says is ‘‘by no means uncommon,” and he 
evidently depends as a specific feature on the quadrangular enlarge- 
ments of the fertile cells. ‘‘ Cells usually seven or eight times as long as 
broad. Sporangia oval, large, and much elongated, contained within 
quadrangular enlargements of the cells.” 
Plate XXXIX. fig. 1. a, fertile cells in conjugation with zygospore 
X 200, after Petit ; b, zygospore in cell x 400. 
Spirogyra Weberi. Kutz. 
Sterile cells with the extremities replicate, 7 to 12 times as 
long as the diameter, chlorophyll bands single, 3 to 8 turns of 
the spiral. 
Spores ovoid, scarce broader than the sterile threads, mem- 
brane even, chestnut, twice as long as broad. 
Sporiferous cells scarcely turgid. 
Size. Spores: (a) 072 x-034 mm. (8) ‘068 x 034 mm. 
‘Cleve Monog. Zygn. p. 25, t. vii., f. 1-10. 
form a. inequalis. 
Diameter of thread ‘03 mm.  Sporiferous cells scarcely 
longer than the spores. 
Zygnema inequale, Hass. Alg. 150, t. 32,f.1 to 2. 
Zygnema intermedium, Hass. Alg. t. 37, f. 3. Ann, Nat. 
Hist, x. (1842) p. 41. Jenner Fi. ‘Tunb, Wells, 182. 
