OF THE THIRD TANGANYIKA EXPEDITION. 151 
specimens of a Synedra from the Irish Lakes which were referred by 
Lemmermann to 8. revaliensis. It seems to be identical with the Synedra 
mentioned by Ostenfeld and Wesenberg-Lund as occurring in two Icelandic 
lakes (vide Proc. Roy. Soc. Edinb. xxv. part xii. (1906) p. 1114, t. 2. 
figs. 16, 17) ; and I am inclined to agree with those authors that it is merely 
a form of S. Acus var. delicatissima, the stellate colonies resulting from an 
adaptation to a limnetie life. Some of the radiating colonies contained 
upwards of 50 individuals. It may also be identical with the Diatom 
recorded by Schmidle from Lake Nyasa as “ Synedra ? asterionelloides, 
O. Müller, n. sp." (cf. Engl. Bot. Jahrb. xxxiii. (1902) p. 8). 
In both this Diatom and the succeeding species (S. actinastroides) the 
individuals are arranged in radiating colonies after the manner of the genus 
Actinastrum, and Lemmermann places them along with the two species 
S. limnetica, Lemm., and S. berolinensis, Lemm., in a subgenus “ Belonastrum " 
of Synedra. 
202. SYNEDRA ACTINASTROIDEs, Lemm. in Вет. Deutsch. Bot. Ges. xviii. 
(1900) p. 30 ; Forschungsber. Biol. Stat. Plón, xi. (1904) p. 311. 
Long. 44-49 р; lat. 2:3 p. 
Tanganyika.—In plankton, off Niamkolo (2 and 9 Aug. 1904 ; nos. 36 and 
52), in Kituta Bay (25 Aug. 1904; по. 77), near Mbete (28 Sept. 1904 ; 
по. 109), near Kasawa (no. 132), near Kassanga (14 Nov. 1904 ; no. 159), 
near Maswa (14 Jan. 1905 ; no. 211), and in middle of lake between Rumonge 
and Uvira (30 Jan. 1905 ; no. 218). 
203. SyNEDRA CuxNINGTONI, sp. п. (РІ. 8. fig. 4.) 
Cellula ut visa aspectu valvulari angustissima linearis, in parte mediana 
tertia cum inflationibus insignis latis binis, partibus apicalibus angustissimis 
cum marginibus parallelis, apicibus minute capitatis, striis 12-13 in 10 p, in 
partibus apicalibus elongatis vix conspicuis, pseudorhaphide lata in parte 
mediana inflata cellulae ; ut visa aspectu cingulato anguste linearis, parte 
mediana subanguste inflata, polis truncatis. 
Long. 200-210 ш; lat. in med. 45 р; lat. max. 6'5 ш; lat. part. apical. 
1:4 p; lat. арго. 18 д. 
Victoria Nyanza.—Among Utricularia, in sheltered bay near Entebbe 
(1 May, 1905 ; no. 620). 
This Synedra is remarkable for the double inflation of the median part of 
the valves, the extremities being very long and narrow, with parallel margins. 
The inflation is not merely visible in the valve-view, but is likewise very large 
in the girdle-view. In the girdle-view, however, the median inflation has 
subparallel margins in the central part and does not show any signs of the 
constriction which is such a peculiar feature of the valve-view. Each of the 
narrow extremities of the valve is very faintly (almost imperceptibly) swollen. 
I know of no species to which it is very closely related except forms of 
S. Acus, and from these it is at once distinguished by its peculiar form. 
