The Freshwater Algae of Africa. 



519 



of the longitudinal walJs and the possible occurrence of reproduction 

 by fission, may ultimately warrant the establishment of a distinct 

 genus for this species. 



Genus HORMIDIUM Klebs. 



(ULOTHRIX, sect. HORMIDIUM, Kuetz.) 



1. Hormidium subtile (Kuetz. ?), Heering, Suesswasserfi. Deutsch- 

 lands, Oesterreichs, u.d. Schweiz, vi, 1914, p. 47, fig. 54. (Syn. : 



Fig. 12.-- Hormidium subtile (Kuetz. :-), Heering. a. Part of an ordinary 

 filament, b-d. Stages in splitting. All figures x 800. 



Stichococcus siibtilis, Klercker, Ueb. zwei Wasserformen v. Sticho- 

 coccus, Flora, lxxxii, 1896, p. 92 et sea., Tab. VI, figs. 1-8; Ulothrix 

 subtilis, Kuetz. pro parte). (Fig. 12.) 



Samples 56, 57. 



It would appear that comprised in Kuetzing's Ulothrix subtilis 

 there are two distinct forms, viz. a true Ulothrix with cpuadriciliate 

 inacrozoospores, and another aquatic form with biciliate* macrozoo- 



* Cf. Hazen, Ulotrich. and Chaetoph. United States, Mem. Torrey Bot. 

 Club, xi, 1902, pp. 158, 159. 



