THE ALGA-FLORA OF CAMBRIDGESHIRE. 109 
species was not observed in the conjugating state; but the attheriie 
slenderness of the sterile cells, sees were thirty to thirty-five times 
longer than a meri does not admit of its being any other 
species. Moreover, the slombisbphvords were restricted to the 
median portion of ‘the cells exactly in the manner figured by Wiitt- 
rock, Distrib. Westmoreland, West Ireland, and Sweden 
Subfam. Zyenemem, 
61. Zyanema cructatum (Vauch.) As. 3. Wimpole Park: June, 
1898. Sterile oe of a Zygn which was probably this 
species, were observed from the ate i. the Botanical Gardens, 
and ae: eep’s eedhe ieee 
<h. 8 ronan (Kiitz.) Han. Syn. Zygogonium ericetorum 
Ritz 5. Chippenham Fen, “4h6 agai form [forma fluitans (Kiitz.) 
Rabenh. 5 heeds Aug. 1898. 
63. Z. Ratrsu (Hass sj De Bary. 8. Chippenham Fen. The 
zygospores were Re larger than the average size for this species. 
Crass. cell. veget. 16 «; long. zygosp. 29-81 y; lat. bie! 23-24 ps, 
64. SrinoovRA arcta (Ag.) Kutz. var. caran s (Hass.) 
re Paes . cateniformis (Hass.) Kitz. 6. Roswell Pits, Ely. 
sus die ass.) Kiitz, 2. Dernford Fen, 1 mile 8. of 
shcecd ‘s. Chippenham Fen. 6. In ponds near Ely. 
66. S. communis (Hass.) Kiitz. 6. Ditches near Ely. 
67. S. nrrma (Dillw.) Link. 6. Ditches near Ely. 
68. S. masuscuza Kiitz. Syn. S. orthospira Nag. 5. Chippenham 
Fen: very fine, Aug. 1898. Several irregularities were noticed in 
the conjugation, more particularly the go of double spores, 
one in each filament; cfr. West and G. S. West, ‘Obs. on Conj.,’ 
Ann. of Botany, xii. 1898, t. v.f.78-80. Spores s were also. cheney 
which had been formed from only ae e = contents of the con- 
en cells ; cfr. West & G. S. Wes 7 
69. ra (Hass.) Wittr. ei if oftioalabes (Hass.) Kitz. 
6. Roswell Pits, ‘Ely: July, 1898. ‘The ripe zygospores are of the 
same rich brown colour as those of S. majuscula, and, although they 
are of considerably greater diameter, the spore-wall is comparatively 
thinner. The pr roportion of the thickness of the spore-wall to the 
ainesotes of the fi spore is as 1:17°44; in the case of S. mestiseate 
it is te 1:12°5 
. 8. gracmis (Hass.) Kitz. 8. Sheep’s Green, Cambridge ; 
Winget Park. 
. omg _(Hass.) Kutz. Spec. Algar. 489; Rabenh. 
Flos, paca Algar, ili. 247. Syn. Zygnema pellucida Hass. Brit. 
Freshw. Alg. 143, ie xxv. f.1,2. (Pl. 895, figs. 1-8. 
8. dense cwespitosa, lu brica, flavo-viridis; cellulis vegetativis 
diametro 84-9-plo (usque ad 12-plo) longioribus, extremitatibus 
non replicatis; chromatophoris 8-4 (plerumque 4), sublatis cum 
marginibus multe irregularibus et pyrenoidibus magnis, subrectis 
vel anfractibus laxissimis 4-14 (rarissime 2-4); conjugatione 
scalariformi, cellulis fructiferis valde tumidis in parte 
