ZYGNEMACESS. 89 
Zygnema neglectum, Hass. Alg. t. 23, f. 1 (not Petit). Hass. 
Ann, Nat. Hist. x. 37, Jenner Fl. Tunb. Wells 178. 
In ponds. Fruiting in August. 
This species is rather a characteristic one, of which it appears to us 
that Zygnema neglectum, Hass., is only a form with three chlorophyll 
bands. If the two species of Hassall are drawn to the same scale, it is 
difficult to indicate any specific difference. The Rhynchonema rostratum 
of Kntzing is referred by Cleve to this species, but the Zygnema 
rostratum of Hassall appears to be different, with thicker filaments and 
much longer zygospores, and is rather referable to Spirogyra nitida. 
ie Spirogyra neglecta of Petit cannot be the Zygnema neglectum of 
assall. 
This species is thus described by Hassall :—“ Filaments about a foot 
in length, with truncate extremities; of considerable though rather less 
diameter than those of 9. nitida, mucous, glossy, and of a deep and 
beautiful green colour; investing membrane of the cells very evident 
and transparent. Cells in the young filaments scarcely so long as broad, 
but their length exceeds their breadth in those which have conjugated ; 
round the interior of the cells five or six loose spiral tubes may be 
faintly discerned ; these contain the reproductive globules (sic), which 
are large and distinct, with a dark central nucleus. Sporangia oval 
sometimes almost circular and flattened, lying in inflated cells, the 
cavity of which they do not fill.” 
Plate XXXIV. fig.2. a, sterile cells X 200; 0, conjugating cells with 
zygospores X 200; ¢, fertile cells of Rhynchonema form with zygospore 
X 200; d, outline of zygospore x 400. 
B. Chlorophyll bands single or double (rarely ternate). 
Spirogyra porticalis. Vauch. 
Sterile cells with the extremities truncate, 2 to 4 times 
longer than the diameter ; chlorophyll bands single, or binate, 
rarely ternate. 
Spores obtuse, ovoid, 14 times longer than the diameter, 
membrane even, chestnut colour. 
Sporiferous cells equal to the length of the spore, or twice as 
long, more or less turgid. 
Size. Cells :032--05 mm. diam. Zygospore ‘08 x -048-05 
mm. 
Cleve Monog. Zygn. p. 22, t. 5, f. 8 to 13. 
Conjugata porticalis, Vauch. Conf. p. 66, t. 5, f. 1. 
In ditches, &c. Fruiting in spring. 
vor. a quinina. 
Chlorophyll bands usually single. 
Sizz. Cells :035-:045 mm., about twice as long. 
Zygnema quininum, Hass. Alg. t. 28, f.1, 2. Harv. Man. p. 
143. Landsborough Brit, Seaweeds p. 862. Eng. Fl. v. 362. 
Eng. Bot. Ed. ii. p.175. Harv. Man. 143. Johnst. Fl. Berw. 
ii. 256. Grev. Fl. Ed. 320. Mac. Fl. Hib. 231. Fl. Devon 
ii. 50. Hook. Fl. Scot. ii. 80. Dickie Bot. Guide, 296. 
