ZYGNEMACE.E. 1U5 



We can recognize no plausible grounds on which the M. intricatus of 

 Hassall can be maintained as a species distinct from M. scalaris. 



Plate XLI I. fig. I. a, sterile cells X 400; b, conjugating cells, with 

 zygospores x 400. 



JVIesocarpus recurvus. Hass. 



Sterile cells 5 to 10 times as long as broad. 

 Zygospore globose. Sporoderm brown, even. 

 SIZE. '012-'018 mm. Zygospore '023 mm. diam. 



Hass. Alg. 168, t. 44, f. 1. Rabh. Alg. Eur. iii. 257. 

 Sphcericarpus recurvus, Hass. Ann. N. Hist. xii. 186, t. 7,f. 10. 



In ditches. 



Plate XL II. Jig. 2. a, sterile cells X400; 6, conjugating cells with 

 zygospores X 400. 



Sub-Genus PLEUROCARPUS. Braun. 

 Mesocarpus pleurocarpus. De Bary Conj.p. 81. 



Sterile cells 2 to 3 times as long as broad. 



Zygospores subglobose, brown, even. 



SIZE. Cells - 025-'03 nun. Zygospore -03 mm. diam. 



Pleurocarpus mirabilis, Braun. Alg. Uni. p. 60. Rabh. Alg. 

 iii, 258. 



Zygogonium pleurospermum, Kutz Tab. v. t 13. 



Mougeotia genuflexa, Ag. and others. Eng. Fl. v. 360. Eng. 

 Bot. Ed. 11. t. 2505. Jenner. Fl. Tunb. Wells, 182. Hass. 

 Alg. 172, t. 40, f. 2. Harv. Man. 141. Mack. Fl. Hib. 231. 

 Dickie Bot. Guide, 296. 



Conferva genuflexa, Dillw. Conf. t. 6. Eng. Bot. Ed. 1, t. 

 1914. 



Zygnema genufiexum, Johnst. Fl. Berw. ii. 257. Grev. Fl. 

 Ed. 320. 



Serpentaria genuflexa, Gray Arr. 1, 300. 



var. compressus. 



Mougeotia compressa, Eng. Fl. v. p. 360. Eng. Bot. Ed. 2, 

 p. 172. Harv. Man. 141. 



Zygnema compressum, Lyngb. Hyd. Dan. t. 58. 

 Serpentaria compressa, Gray Arr. 1. 300. 

 Pleurocarpus compressus, Rabh. Alg. Eur. iii. 258. 



In moor pools, &c. 



This widely diffused species forms vast yellowish-green masses, which 

 Harvey says are often thirty feet in diameter ; we have often met with 

 them covering several square feet. The filaments are fragile, soon 

 breaking into short lengths, bent almost at right angles and united at the 

 angles, hence the old name of Mougeotia genuflexa. 



Plate XL III. fc/. 1. Cells in conjugation X 400; 6, fertile cells 

 with zygospore, after De Bary X 400; c, c, zygospores X 400. 



