562 



Annuls of Ihr Smith African Museum. 



gamenfl., vi, 1907, Tab. XXVII, B, fig. 2), and to 8. subamoenum, 

 Maskell (Trans. New Zealand Fust., wi. L888, p. ±1, fig. 37), from 

 both of which it however differs in important respects. Compare also 

 .S'. tristichvm, Elfv. 



4. Staurastrum gracile, Ralfs, Brit. Desm., 1848, p. 136, Tab. XXII, 

 fig. 12. 



Samples 14, 15, '21. 24, ,r2 (rare in all cases). 



Long., '■'<*'> ji : lat. cum proc, 60// ; lat. sine proc, 20 /a ; Lat, isthm.. 

 12 p. 



Genus SPONDYLOSIUM Brebisson. 



1. Spondylosium pygmaeum (Cooke), West, Freshw. Alg W. Ireland, 

 Journ. Linn. Soc, Bot., xxix, 1891, p. lit!. (Syn. : Sphaerozosma 



Fig. 33. — Spondylosium pygmaewm (Cooke), West. var. capensis, nov. var. 

 a, (/, e, cells and semicells in end view ; b, c, isolated cells ; f, g, chains. 

 All figures x Tan. 



pygmaewm, Cooke (Brit. Desm., 1887, p. 5, PI. II, fig. 5), non 

 Rabenh.) (Fig. 33). 



Samples 8 and 10 (in clusters on surface of Tribonema bomby- 

 ci a a in ), 57. 



The cells are rather larger than those recorded by Cooke (long., 

 11-12 /x ; lat., 10-12 [a ; lat. isthm., 4-5 /i ; crass.. 6 p) and were rarely 

 connected in chains of more than three or four (Fig. 33, g), often 

 merelv forming irregular groups attached to the surface of the sub- 

 stratum. Numerous isolated cells were encountered, and in sample 

 57 practically no chains were observed. In some of the longer chains 

 a tightly -fitting mucilage envelope could be distinguished (Fig. 33, ;/). 

 As regards shape of cell, the apices were, on the whole, rather flatter 

 than appears in Cooke's figures. Whilst in many cases the end-view 

 was a broad ellipse, numerous individuals were encountered in which 

 it was triangular (cf. Fig. 33, a, d, e). In view of these differences, 

 the form in the present material should perhaps be distinguished as a 

 var. capensis, nov. var.. with the following diagnosis: 



