86 Annals oj the Smith African Museum. 



136. Gosmarium formosulum, Hoff. 



Long. 51-53 /z; hit. 43-44 tz; lat. isthm. 11-5-12 /j ; crass. 26 /x. 



Karoo. Among Spirogyra sp. in sulphureous spring at Gans- 

 fontein; 2.12.08. 



Cape Eegion hetween Ceres and Karoopoort. In sulphureous 

 spring at Leeuwefontein, abundant among Spirogyra sp. ; 28.12.08. 



137. Gosmarium geometricum, W. & G. S. West, var. adoxoides, 

 G. S . West, var. n. 



Var. sinu lineari ad extremum ampliato ; apice semicellularum 

 leviter concavis vel rectis. 



Long. 9-5-10 it ; lat. 9-10 M ; lat. isthm. 2-5 /x ; crass. 5-2 tx. (Pig. 47.) 



Little Namaqualand. Among Char a sp. in dam at Pella ; 8.1.09. 



The semicells of this tiny desmid have the minutely apiculate 

 angles and also the slightly papillate central area of G. geometricum, 

 but the closed sinus of C. ad ox inn.. 



G. geometricum was originally described from Madagascar. 



138. Cosmarium lave, Rabenh. 



Little Namaqualand. In dam at Pella ; 8.1.09. 



Var. distentum, G. S. West, var. n. 



Var. semicellulis latioribus, lateribus subdilatatis ; a vertice visis 

 cum tumore parvo ad medium utrobique. 



Long. 26-29 tt; lat. 21-24// ; lat. isthm. 6-7 /< ; crass. 15'5/x. 

 (Fig. 48.) 



Little Namaqualand. In dam at Pella; 8.1.09. Among various 

 algae, Dabainoris ; 11.1.09. In dam at Kamiebies ; 24. 12. OS. 



Great Namaqualand. In cattle-trough at Griindoorn ; 4.2.09. 



This desmid occurred abundantly in the above-mentioned localities. 

 Forms of G. lave appear to be very widely distributed and by no 

 means uncommon throughout the African continent. 



139. Cosmarium Logiense, Bissett, forma expansa, W. & G. S. 

 West, Monogr. Brit. Desm. IV, 1911, p. 16, t. 99, f. 7. (- C. latum 

 var. minor, Roy & Biss., Scott. Desm. 1894, p. 105, t. 2, f. 11.) 



A rather small form : long. 50 /z ; lat. 46 /i ; lat. isthm. 17 it. 



Karoo. In sulphureous spring at Gansfontein; 2.12.08. 



This form should be compared with that described and figured by 

 Gutwinski from Poland as " G. Logiense forma?" (vide Rozpraw 

 Wydz. mat.-przyr. Akad. Umiej. Krakow, xxxiii, 1896, p. 25, t. 7, 

 f. 33). 



140. Gosmarium obtusatum, Schmidle. 

 Long. 67/t ; lat. 56 ^; lat. isthm. 14 /.«. 



Karoo. In sulphureous spring at Gansfontein ; 2.12.08. 



