80 THE JOURNAL OF BOTANY 



t. 5, f. 11-13. When Spkinctosi;phon ijolymorphus was described 

 it was stated that " the exact nature of the chromatophore could 

 not be determined from the preserved material. It is undoubtedly 

 massive and occupies most of the cell, being for the greater part 

 parietal in disposition." It was also described as "laete viridi et 

 valde granuloso." Shortly after the description appeared, Osten- 

 feld " pointed out that the Alga could not very well be a member 

 of the PalmellacecB, but rather belonged to the genus Microcystis 

 in the Chroococcacece. A re-examination of the specimens from 

 Victoria Nyanza has shown that Ostenfeld's suggestion was a 

 correct one. The cells are pale green in colour, and the massive 

 nature of the supposed " chromatophore " is due to the pigment 

 occupying all the cytoplasm external to the central body, exactly 

 as it does in other members of the ChroococcacecB. The large, 

 dark granules are most probably gas vacuoles. 



On transferring the Alga to the genus Microcystis, one finds 

 that a species was described in 1898 under the name of '* Poly- 

 cystis ochracea," which almost exactly fits the African plant. 

 Moreover, it is a plankton-species, and has been recorded from 

 the Wurmsee, in Bavaria, and from Lake Varano, in Italy. It 

 agrees in all its essential characters and in its dimensions. The 

 cells also are described as "dilutissime viridibus, granulis nitenti- 

 bus insparsis." 



There is one point of difference in the gelatinous integuments. 

 In the African plants the outer portions of the envelope were firm 

 and often distinctly lamellose, the outermost lamella frequently 

 becoming mucilaginous. However, all things considered, Sphincto- 

 sijplion polymorj^hus must be placed as a synonym of Microcystis 

 ochracea. 



2. Spieulina major Kiitz. Crass, trich. 1-7-2 /x. Hab. Albert 

 Nyanza. 



3. Plectonema Wollei Farlow. Hab. Albert Nyanza. 

 Fragmentary material of this Alga is apparently indistinguish- 

 able from Lyngbya majuscula Harvey. 



4. Amphora ovalis Kiitz. Hab. Albert Nyanza. 



5. Navicula rhynchocephala Kiitz. var. rostellata (Kiitz.) 

 V. Heurck. Hab. Albert Nyanza. 



6. Tetraedron enorme (Ealfs) Hansg. Hab. Albert Nyanza. 

 I give a figure of one of the stout inflated specimens which 



appear to be frequent in this lake. (Fig. 1, A.) 



7. Crucigenia emarginata (W. & G. S. West) Chodat, Algues 

 Vertes de la Suisse, 1902, p. 207. Staurogenia emarginata W. & 

 G. S. West in Trans. Linn. Soc. Bot. ser. 2, v. 1895, p. 81. t. 5, 

 f. 25, 26; Schmidle in Ber. Deutsch. Botan. Ges. xviii. 1900, 

 p. 156. Long. cell. 12-5-14-5 /x ; lat. cell. 11-12 fx. 



Hab. Lake Alastra, Madagascar. 



• C. H. Ostenfeld, " Phytoplankton aus dem Victoria Nyanza," Engler'a 

 Botan. Jahrbiich. xli. 1908, p. 333. 



