74 Annals of the South African Museum. 



77. Nitzschia Denticula, Grun. (= Denticula obtusa, W. Sm.) 

 Little Namaqualand. With the preceding species. 



78. Nitzschia constricta, (Kiitz.) Pritch. (= N. dubia, W. Sm.) 

 Little Namaqualand. In dam at Kamiebies ; 24. 12. OS. 



79. Nitzschia linearis, (Ag.) W. Sm. 

 Angola. In stream in Cazengo District. 



Little Namaqualand. In pools at Brakrivier ; 11.12.09. In dam 

 at Henkriesfontein ; 14.1.09. 



80. Nitzschia Kutzingiana, Hilse. 



Angola. In concreted water-conduit, Mossamedes. 

 Upper (or Composite) Eegion. On drying mud, Holle River ; 

 10.12.08. 



81. Nitzschia Palcea, (Kiitz.) W. Sm. 



Karoo. In sulphureous spring at Pappekuil ; 2.12.08. In 

 similar spring at Beukesfontein ; 1.12.08. 



Upper (or Composite) Eegion. On drying mud, Holle River ; 

 10.12.08. In dam at Karieboomfontein ; 8.12.08. 



Little Namaqualand. In spring at Henkriesfontein ; 14.1.09. 



Var. tenuirostris, Grun. 



Upper (or Composite) Region. In dam at Karieboomfontein ; 

 8.12.08. 



Little Namaqualand. In running water at Henkriesfontein ; 

 14.1.09. 



Var. debilis, Van Heurck. 



Karoo. In spring at Beukesfontein ; 1.12.08. 



82. Nitzschia stagnoruiii, Rabenh. 



Angola. In concreted water-conduit, Mossamedes. 

 Upper (or Composite) Region. Holle River ; 10.12.08. 

 Little Namaqualand. In pool at Aggenys ; 6.1.09. 



83. Nitzschia Tvyblionclla, Hantzsch. 



Upper (or Composite) Region. Holle River; 10 12.08. 



Var. victoria, Grun. 



Angola. In stream in Cazengo District. 



84. Hantzschia Amphioxys, (Ehrenb.) Grun. 



Little Namaqualand. In dam at Rozynbosch ; 9.1.09. 

 Great Namaqualand. On drying mud at Lowen's River, 

 Gawachab; 7.2.09. 



