120 SIPHOPHYCE. 
The plates for this part were all in course of printing when the above 
observations were being made, so that it was too late to insert figures of 
the septate threads and their contents. 
Plate XLVI. Figs. 1-20. Impregnation of Vaucheria sessilis after Pring- 
sheim X 200. 
Figs 1-4. Stages of development of sexual organs before impregnation. 
Fig. 5. During impregnation. Figs. 6-8. The way in which the female 
organ opens the cutaneous layer, bursts through, and a portion is con- 
stricted of. Fig. 9. Approach of spermatozoids before formation of the 
membrane of the embryo cell. Fig. 10. Point of female organ after 
formation of the membrane of the true spore. Figs, 11-12. Later con- 
ditions of spore after impregnation. Figs. 13-16. Male and female 
organs after impregnation. Fig. 17. Colourless spore after it is detached 
from the parent tube. Fig. 18. Detached spore, which after resting three 
months has become green. Figs. 19-20. Germination of the green spores. 
a, TusunicerRs. Antheridia little or scarcely bent. 
1. Vaucheria dichotoma. Lyngb. Hydro. Dan. p. 75, t. 19. 
Robust, loosely cespitose, dirty green, or becoming brownish. 
Thallus very thick, setaceous, nearly a foot long, remotely 
dichotomous. Oogonia sessile, globose, or ovoid, single, scat- 
tered, or 2 to 4 to 6 approximating. Oospores, when mature, 
with a triple membrane, spotted with brown. Antheridia single, 
erect, oval, sub-clavate, or acute, on the same or on different 
threads.—Rabh. Alg. Eur. ut. 268. 
Sizz. Oogonia‘l mm. diam. Threads ‘2 mm. diam. 
Walz in Pringsh. Jahrb. p. 152, t. xiv. f. 28-83. FI. 
Danica t. 1724. Harv. Man. p. 147. Grev. Br. Alg. p. 190. 
Gray. Arr. i, 289. Kirsch, Alg. Schl. p. 82. Eng. Bot. ii, t. 
2418. Grev. Fl. Ed. 305. Mack. Hib. 233. FI. Devon ii., 
56. Kutz. Tab. vi., t.56a. Hass. Alg. t.4,f.1. Eng. Fl. v., 
p. 319. Nordst. Bot. Not. 1879, p. 184. Jenner Fl. Tunb. 
Wells, 176. 
Conferva dichotoma, Linn. Spec. 1635. Dillw. Conf. t. 15. 
Eng. Bot. t. 982. Huds. Fl. Ang. p. 593. Withering iv., p. 
49. Hull Br. Flora, 330. 
Vaucheria globifera, De Bary Monats. 1856, p. 589. Rabb. 
Alg. Ex. No. 640. 
Vaucheria salina, Kutz. Tab. vi., t. 66, f. 2. 
Conferva Plinii setis porcinis, Ray. Syn. 58. 
Conferva dichotoma setis porcinis, Dillen. Musc. 17, t. 3, f. 9. 
var. 8 submarina, Ag. Syst. p. 171. 
Vaucheria submarina, Berk. Glean. p. 24, t.8. Harv. Phye. 
Brit, t.350 B. Harv. Man. 147. 
In ditches, and in brackish and salt water. 
Hassell was of opinion that this species did not differ specifically from 
Vaucheria sessilis, but the two are now regarded as belonging to different 
sections, Nordstedt says that it is diecious, but no reference is made to 
this fact by Walz. 
