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 XLVL 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 off. 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. 1 8. Detached spore, which after resting three 

 months has become green. Figs. 19-20. Germination of the green spores. 



a. TuBULiGER-. Antheridia little or scarcely bent. 



1. Vaucheria dichotoma. Lyngb. Hydro. Dan. p. 75, t. 19. 



Robust, loosely czespitose, 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. in. 268. 



SIZE. Oogonia ! mm. diam. Threads '2 mm. diam. 



Walz in Pringsh. Jahrb. p. 152, t. xiv. f. 28-33. Fl. 

 Danica t. 1724. Harv. Man. p. 147. Grev. Br. Alg. p. 190. 

 Gray. AIT. i., 289. Kirsch. Alg. Schl. p. 82. Eng. Bot. ii., t. 

 2418. Grev. Fl. Ed. 305. Mack. Hib. 233. Fl. 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. 932. Huds. Fl. Ang. p. 593. Withering iv., p. 

 49. Hull Br. Flora, 330. 



Vauclieria globifera, De Bary Monals. 1856, p. 589. Rabh. 

 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. Muse. 17, t. 3, f. 9. 



var. /? sub marina. Ag. Syst. p. 171. 

 Vauclieria submarina, Berk. Glean, p. 24, t. 8. Harv. Phyc. 

 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 dioecious, but no reference is made to 

 this fact by Walz. 



