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Transactions of the Boyal Society of South Africa. 
surface bears a punctation which appears to be due to very numerous 
minute pits in the wall (c/. Fig. 7, E-H). The pits are quite irregularly- 
arranged over all parts of the cell. The colouration of the membrane is in 
general rather faint. The protoplasmic contents were often highly 
vacuolate. 
In shape f. genuina is not unlike some forms of C. spetshergense, Borge 
(' Vid.-selsk. Skrif t. , Kristiania, I, Mat.-nat. Kl.,' 1911, No. 11, p. 8, fig. 5 a) ; 
this species is, however, considerably smaller and has a colourless glabrous 
membrane. Comparison may also be made with C. massarti, De Wildeman, 
C.fusiforme, Gay, and C. methueni, Fritsch. 
10. Closterimn rostratum, Ehrenb., W. & Gr. S. West, loc. cit , p. 188, 
PI. XXVI, figs. 1-5. 
Samples 338 and 339 (in both cases with zygospores), 340. 
Recorded from Madagascar (Fritsch). 
Genus PLEUROTAENIUM Naegeli. 
1. Pleurotaenium ehrenbergii (Breb.), De Bary, Unters. ueb. d. Fam. d. 
Conjug., 1858, p. 75; W. & G. S. West, loc. cit., p. 205, PI. XXIX, 
figs. 9-11. 
Samples 26, 327 (in the latter not uncommon). 
Previously recorded from the Cape (Nordstedt and Fritsch). 
2. Pleurotaenium ovatum, Nordstedt, Alg. aq. dulc. Brasil., Oefvers. K. 
Sv. Vet.-Akad. Foerhandl., 1877, No. 3, p. 18. (Syn. : Docidimn ovatum, 
Nordst., Vid. Med. Nat. Foren. Kjobenhavn, 1869, ^. 205, Tab. Ill, fig. 37.) 
Sample 327. 
Long, cell., 270-340 /x; lat. max., 81-87 /x ; lat. constr., 45-60 /x; lat. 
apic, 25-27 /x. These dimensions are appreciably less than those originally 
recorded by Nordstedt. Slightly smaller specimens have been described by 
Schmidle (Engler's ' Bot. Jahrb.,' xxvi, 1899, p. 23) as var. minor, but it is 
doubtful if this variety can be retained, since the size of the species is 
subject to much fluctuation. 
The specimens in sample 327, while showing the typical shape, exhibited 
the annular thickening at the constriction figured by W. & G. S. West for 
var. tumidum, Maskell (' Ann. Boy. Bot. Garden, Calcutta,' vi, Part II, 
1907, PI. XIII, fig. 8) and by Turner for his Bocidium rotundatum (' Sv. 
Vet.-Akad. Handl.,' xxv, No. 5, 1892, t. vii, fig. 2 a), which is probably synony- 
mous with the former. They also differed in the fact that the membrane 
appeared to be not punctate, but delicately and irregularly striate. 
This species has been recorded from the Cape by Nordstedt and 
Fritsch. 
