182 NEMATOPHYCE. 
Vlothrix variabilis. Kutz. Tab. Phyc. 1., t. 85, f. 3. 
Pale green; cells equal or a little longer than their diameter, 
rarely twice as long; cell-contents at first always contracted in 
a quadrate manner. 
Sizz. Cells 005-007 mm. 
Rabh. Alg. Eur. iii. 
Ulothrix subtilis, var. ¢. variabilis, Kirch. Alg. Sch. 77. 
In ditches and slow streams. 
The view entertained by Kirchner that this and U. tenerrima are 
only varieties of Ulothria subtilis is probably correct. 
fe Plate LEX. fig. 4. Portions of threads of Ulothrir variabilis X 400 
jam. 
Ulothrix tenerrima. Kutz. Tad. Phy. 11, t. 87, f.1. 
Pale green, or yellowish-green, Inbricous ; cells mostly equal 
in length and diameter, now and then a little shorter. 
Size. Cells -007--01 mm. 
Rabh. Alg. Eur. iii., 366. 
Ulothrix subtilis, var. e. tenerrima, Kirch. Alg. Schl. p. 77. 
In ditches, turbaries, &c. 
Plate LXX. fig. 5. Portions of threads of Ulothrix tenerrima x 400 
diam. 
Vlothrix tenuis. Autz. Tab. Phyc. 11., t. 89, f. 1, dis. 
Dark green, attached, from half to two or three inches long, 
mucous, cells equal or 2-4 times shorter than their diameter, 
cell membrane thin, homogeneous. 
Size. Cells -017--026 mm. 
Rabh. Alg. Eur. iii., 366. Kirch. Alg. Scbl. p. 78. 
In ditches and streamlets. 
Plate LXX. fig. 6. Portions of threads of Ulothria tenuis X 400 
diam. 
Ulothrix (Hormidium) radicans. Kutz. Jab. Phyc. u., t. 95, f. 3. 
Yellowish green, rather rigid, densely interwoven in a soft 
velvety green stratum, cells either nearly equal or 2-3 times 
shorter than their diameter. 
Sizz. Cells :0075--0095 mm. 
Rabh. Alg. Eur. iii., 8367. Kirch. Alg. Schl. p. 77. 
Hormidium murale, Kutz. Phy. Germ. p. 193. 
Lyngbya muralis, Ag. Syst. p. 74. Eng. Fl. v , 370. Hass. 
Alg. 221, t. 59, f. 7. Eng. Bot. ii, t. 2522. Jenn. Tunb. 
