586 Annals of the South African Museum. 



2. Eunotia (Himantidium) pectinalis, Kuetz. ; Van Heurck, op. cit., 

 p. 142, PL XXXIII, figs. 15, 16. 



Samples 8, 9, 10, 41, 52, 54, 55. 



Particularly good specimens in sample 10, hei'e together with vars. 

 minor, Kuetz. and var. impressa, O. Muell. The species has previously 

 been recorded from South Africa by G. S. West. 



3. Eunotia lunaris (Ehrenb ), Grun. ; Van Heurclc, op. cit., p. 144, 

 PI. XXXV, figs. 3, 4, 6a. (Syn. : Synedra lunaris, Ehrenb.) 



Samples 2 (on Tribonema bombycinum) , 56, 57 (on Hormidium 

 subtile). 



4. Eunotia bicapitata, Grun. ; Van Heurck, op. cit., PI. XXXV, 

 fig. 11. (Syn.: Synedra biceps, W. Smith, Brit. Diatom., i, 1853, 

 p. 69, PL XI, fig. 83) (fig. nostr. 40, h, h'.) 



Samples 2, 8, 9, 10 (in all cases on Tribonema bombycinum). 



This form appears to lie not uncommon in the Cape Peninsula, 

 forming characteristic stellate bunches attached to filamentous Algae. 

 There can be no doubt about their reference to the genus Eunotia. 

 The valves are little curved, as in the figures cited above, and have a 

 rather thick wall, and slightly inflated, somewhat recurved extremities ; 

 the inflation is more marked on the convex than on the concave side 

 (Fig 40, h). The punctate striae extend across the valves without 

 interruption. The valves vary considerably in size, being 140-240 /x 

 long and 6-8 /a broad. Van Heurck suggests that this is a variety of 

 E.fi.exuosa, Kuetz. (forms of which Avere also present in sample 10), 

 but it would seem a better policy to regard this species as a variety of 

 E. bicapitata, Grun. There is considerable resemblance between the 

 latter and E. (Himantidium) major (W. Sm.), Eabenh. (H.majus, W. 

 Smith, op. cit., ii, p. 14, PL XXXIII, fig. 286), and the two may 

 possibly be different habit-forms of the same species. 



B. ACHXANTHOIDEAE. 



(1) ACHNANTHACEAE. 



Genus ACHXANTHES Boky. 



1. Achnanthes minutissima, Kuetz.; Cleve, Synops. Xaviculoid 

 Dial., ii, K. Sv. Vet.-Ak. HandL, xxvii, No. 3, 1895, p. 188; Van 

 Heurck, op. cit., p. 131, PL XXVII, figs. 37, 38. 



Samples 10 (on Tribonema), 14 and 15 (on Oedogonium), 31 (on 

 Cladophora), 52-55 (on Tolypotlirix). 



