Zygnema.] ALGvE CHLOROSPERMEjE. 231 



On sand-covered rocks, near high-water mark. Bantry ; Miss 

 Hutchins. Filaments very slightly branched, the lower branches 

 root-like and sparingly articulated, the upper patent, with remarkably 

 rounded axils. 



64. MOUGEOTIA. Ag. Mougeotia. 



Filaments articulated, simple, finally united by transverse tubes. 

 Endochrome granular, at length forming roundish globules 

 at the point of conjugation. Named in honour of J. B. 

 Mougeot y an excellent German botanist. 



1. M. genuflexa, Ag. Knee-bent Mougeotia. Filaments 

 slender, fragile, at length genuflexed and irregularly united by 

 short transverse tubes ; endochrome half filling the articulation ; 

 globules sphaerical. Ag. Syst. p. 83. Harv. in Hook. Br. Fl. 

 v. ii. p. 360. Cow/I genuflexa, Dillw. t. 6. 



In ditches and pools, forming vast yellowish strata. 



65. TYNDARIDEA. Bory. Tyndaridea. 



Filaments simple, finally inosculating by transverse tubes. En- 

 dochrome consisting of two sub-rotund masses (stellce), which 

 after conjugation unite and form a roundish globule (spori- 

 dium), lodged either in one of the articulations, or in the 

 connecting tube. Name ; Tyndaridce, the constellations of 

 Castor and Pollux, in allusion to the twin, star-like globules 

 of the Endochrome. 



1. T. cruciata, Harv. Cross-like Tyndaridea. Stellae round- 

 ish ; sporidia subglobose, lodged in one of the filaments. 

 Harv. in Hook. Br. Fl. v. ii. p. 361. Conf. bipunctata, Dillw. 

 t.2. 



In ditches and pools. 



2. T. pectinata, Harv. Comb-like Tyndaridea. Stellee 

 transversely linear, pectinate ; globules contained in the swol- 

 len transverse tubes. Harv. in Hook. Br. Fl. v. ii. p. 361. 

 Conf. bipunctata, E. Bot. t. 1610. 



In ditches, &c. with the preceding. 



66. ZYGNEMA. Ag. Zygnema. 



Filaments articulated, simple, finally united by transverse tubes. 

 Endochrome forming dotted spiral rings, which after conju- 

 gation are condensed into a globule in one of the filaments. 

 Name ; v<yos, a yoke, and vy^a, a thread; the filaments being 

 yoked together. 



1. Z. nitidum, Ag, Shining Zygnema. Filaments dark 



