146 MR. G. S. WEST ON THE FRESHWATER ALGJE 
Diam. teg. jun. 80-180 ш; diam. teg. adult. (vermiform.) 39-60 ш; diam. 
cell. 55-15 ш; crass. teg. 5-8 p. 
Victoria Nyanza.—In plankton, near Bukoba (18 and 21 Apr. 1905; 
nos. 249 and 252). 
This peculiar genus stands nearest to Palmodactylon, Nüg., but is at once 
distinguished by the hollow integuments with a firm outer gelatinous wall. 
If the Alga be subjected to slight pressure, the cells can be squeezed from 
one part of the hollow vermiform integument to another. The wall of the 
integument often shows a lamellose structure, and in the younger individuals 
the outer coats often become mucilaginous. In the young stages the thallus 
is rounded or irregularly lobed, and while in this condition it frequently 
divides, forming several more or less rounded segments, each of which then 
grows to form an adult plant. The adult thallus is very long, reaching a 
length of 2 mm., and it is more or less cylindrical and vermiform in appear- 
ance. It possesses slight irregular swellings and constrictions of variable 
depths at intervals, and is not infrequently segmented into several elongated 
joints. Sphinctosiphon does not appear to branch. 
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. 
Genus SPHZEROCYSTIS, Chodat. 
186. SPHÆROCYSTIS SCHROETERI, Chodat, in Bull. Herb. Boiss. у. (1897) 
p. 292, t. 9. 
Tanganyika.—In the plankton, Lofu River (5 Oct. 1904; nos. 123 and 124). 
This Alga occurred in great abundance in the two collections of river- 
plankton and, curiously enough, it was not observed in the plankton of the 
lakes themselves. The colonies were the largest I have yet seen and reached 
a diameter of 240 р. It is generally distributed in all the freshwater 
plankton of Europe. 
Genus GLOZOCYSTIS, Nag. 
187. GL@ocystIs GIGAS, (А И.) Lagerh. in Ofvers. K. Sv. Vet.- Akad. 
Fórh. (1883) no. 2, p. 63.—Protococcus gigas, Aütz. Phye. Germ. (1845) 
р. 145. Chlorococcum gigas, (Kütz.) Grun. 
Nyasa.—In swamp, Kota Kota (20 June, 1904; no. 18). In shore-pools, 
Nkata Bay (23 June, 1904 ; no. 22). 
Tanganyika.—In swamp, Kituta (26 Aug. 1904 ; по. 80). 
A form with rather large cells and very tough, brownish or yellowish 
integuments occurred in the plantation from near Sumbu (13 Oct. 1904 ; 
no. 138). 
Victoria Nyanza.—In plankton, near Bukoba (21 Apr. 1905 ; no. 252). 
