Fresh-water Alga'. 63 



sometimes occurred iu great quantity, and appears to be a species 

 very widely distributed in Africa. Species of Bhopalodia are 

 similarly very generally distributed throughout the African con- 

 tinent. Among the more interesting of the Diatoms observed, 

 were Nitzschia Tryblionella var. victoria, a variety of Surirella 

 Engleri, Navicula bahusiensis, and Fragilaria vircsccns var. exigua. 



The Chlorophyceae were fewer than one would have expected, due 

 perhaps to the small rainfall of the areas traversed, and the liability 

 of the water-holes and streams to become dry. The Protococcales 

 were fairly well represented, and the two species of Enteromorpha 

 are particularly interesting. Species of (Edogonium were not 

 common, but fortunately three of them were obtained with 

 reproductive organs. Sterile species of Spirogyra occurred almost 

 everywhere in the pools and streams, but, as in most other tropical 

 areas, no species possessing "replicate" ends to the cells were 

 observed. Only one was in a fruiting state, viz., S. various, one of 

 the most frequent of European species. Considering the nature 

 of the collecting-grounds the family Desmidiaceae was well repre- 

 sented. 



It should also be mentioned that there was an entire absence 

 from the collections of algse belonging to the group of the Hetero- 

 kontae. 



Class MYXOPHYCE^E. 

 Order COCCOGONE^E. 



Family CHROOCOCCACEiE. 



1. Aphanothece caldariorum, Eichter. 



Great Namaqualand. In a pool of a spring smelling strongly of 

 sulphuretted hydrogen at Warmbad ; 28.1.09. Temp, of water 35° C. 



2. Myxobactron hirudiforme, G. S. West, sp. n. 



M. cellulis inter algas chlorophyceas et rnyxophyceas varias libere 

 natantibus, diametro 15-31-plo longioribus, subrectis sed irregulariter 

 et levissime curvatis, polis inaequalibus, una plerumque obtuse 

 rotundata, altera gradatim attenuata et saepe subcapitata ; coutentu 

 cellularum homogeneo et pallide serugineo. Multiplicatio cellularum 

 bipartitione transversa. 



Long. cell. 30-62 p ; lat. 1-8-2 p. (Figs. 54-60.) 



Angola. Floating among other algae in the tank of tbe cable- 

 station at Mossamedes. 



