48 
Transactions of the Royal Society of South Africa. 
cells (c/. Fig. 20, C, F, I). As a general rule the zygospores only occupied 
a part of the fructifying cells (Fig. 20, C, E), but in some cases they 
almost completely filled them (Fig. 20, F, I). The zygospores were 
provided with a smooth thick membrane, generally brownish in colour, 
and varied very much in shape ; the commonest type is shown in Fig. 20^ 
F and F, but almost globular zygospores (Fig. 20, 0) and such as were 
elongated elliptical (Fig. 20, H) were not infrequent. The ends were 
almost invariably broadly rounded (Fig. 20, C, E, F, H), but now and 
again one (Fig. 20, G) or, very rarely, both ends were somewhat pointed, 
this constituting an approach to the form of zygospore characteristic of 
the type. Not uncommonly small drops of oil occurred between the thick 
membrane and the slightly contracted contents (Fig. 20, C, I). The 
ordinary vegetative cells are not inflated, and appear in all cases to 
contain two chloroplasts (Fig. 20, B-D). 
In some respects this variety resembles S. exilis, W. & Gr. S. West 
(Ann. Eoy. Bot. Gard., Calcutta, vi, 1907, p. 186, PI. X, figs. 11-13) ; this 
species is, however, considerably smaller, and shows the inflation of the 
non-conjugating cells only in the female filaments. Possibly, however, 
S. exilis would be better regarded as a variety of S. decimina. 
The latter species is evidently of wide distribution in Africa, having 
been recorded from the Nyassa and Tanganyika region by Gr. S. West, from 
the Nyassa region by Schmidle (f, fuellehornei) , from Madagascar by 
W. & a. S. West, and from Egypt by Qc. S. West. 
2. S'pirogyra suhreticulata F. E. Fritsch, n. sp. (Fig. 21). 
S. cellulis vegetativis diametro ad 8plo longioribus, extremitatibus 
non replicatis, septis saepe crassis ; chromatophoris 3-4, saepe angustis, 
marginibus subintegris, anfractibus 2-3 vel interdum subrectis, cum 
pyrenoidibus conspicuis ; conjugatione scalariformi, cellulis fructiferis 
interdum paullo in media parte inflatis, cellulis vegetativis brevioribus ; 
zygosporis saepe tubis connexivis oppositis, lateres cellularum fructi- 
ferarum arcti tangentibus sed in directione longitudinali eas non com- 
plentibus, oblongo-ellipticis polls acutis vel subrotundatis, interdum fere 
subcircularibus, diam circ. l|-2|plo longioribus ; membrana zygosporae 
crassissima, laminis ternis praedita, lamina externa tenui hyalina per- 
sistente, lamina media irregulariter reticulata luteo-fusca, lamina interna 
crassa brunnea. 
Crass, cell, veg., 50-54 /x; crass, cell, fruct., 51-60 /x; lat. x long, 
zygosp., 60 X 48, 63 x 45, 70 x 42, 87 x 54, 91 x 54, 93 x 49, 94 x 48, 
96 X 54, 124 X 49 /X ; crass, membr. zygosp., 7-9 /x. 
Samples 338, 339, and 340. 
In many respects, and especially in the character of the zygospores^ 
this species approaches S. reticulata, Nordst., but there are several points. 
