76 Annals of the South African Museum. 



90. Glceocystis gigas, (Kiitz.) Lagerh. 

 Angola. In stream in Cazengo District. 



Little Nainaqualand. In dam at Kamiebies ; 24.12.08. 



Family PLEUKOCOCCACE^E. 



91. Pleurococcus angulosus, (Corda) Menegh. 

 Diam. cell. 6-12 p. 



Angola. Forming a thin stratum on the sides of a concreted 

 water-conduit at Mossamedes. 



92. Pleurococcus dissectus, Kiitz. 



Angola. Forming a thin green stratum on sand-grains in a 

 shallow depression which received the water from the bath-rooms 

 of the cable-station, Mossamedes. 



Family AUTOSPOKACEiE. 



93. Oocystis elliptica, W. West, var. africana, var. n. 



Var minima; autosporis 4 vel8, dense compactis ; chromatophoris 

 multe lobatis parietalibus singulis vel binis. 



Long. cell. 8-13 A , ; lat. cell. 4-5-7 ^. (Figs. 14-17.) 



Angola. Abundant among Ankistrodesmus convolutus and Pleitro- 

 coccus angulosus on the sides of a concreted water-conduit at 

 Mossamedes. 



The proportions of the cells of this variety are exactly those of 

 the type. Some of the largest cells show the very faintest indica- 

 tion of polar thickenings, and the old wall of the mother-cell very 

 early becomes gelatinous and disappears, the four or eight autospores 

 remaining for some time in a cluster as though agglutinated 

 together. The cells may possess a single parietal chloroplast, 

 which is much lobed, or two parietal chloroplasts. 



The early disappearance of the walls of the mother-cells 

 distinguishes this African variety from all other known forms of 

 the species. 



Ecdysichlamys, G. S. West, gen. n. 



Cellulas in strato mucosoviridi tenuissimo et expanso confertissime 

 aggregate, oblique ellipsoideae, latere una leviter convexa, latere 

 altera valde convexa (subsemicirculari), polis minutissimeapiculatis ; 

 chromatophora parietali magna et singula in cellula unaquaque, cum 

 pyrenoide singulo (rarissime pyrenoidibus binis) conspicuo, et 

 granulis minutissimis numerosis ; nucleo singulo plerumque 

 unilateraliter dispositis ; membrana cellularum firma, indistincte 



