a4 939 
This species belongs to the subgenus Phaeoceras Gran, which has 
numerous small chromatophores, also in the awns. 
10 (r). 
Area: Red Sea, Malay Archipelago, South China Sea. 
57. (. Schmidtii Ostf. in Ostenfeld & Schmidt, Plankt. f. the Red 
Sea, etc. p. 155, f£.8; 2C. Weissflogii Cleve, Pl. f. the Indian Ocean and 
the Malay Archip. p. 15 and p.55, non Schiitt. 
This species which I have described from the Red Sea, occurs also 
in the Gulf of Siam; and I suppose that it is“the same which Cleve 
l. c. has identified with C. Weissflogii with hesitation. 
10 (r). 
Area: Red Sea, Malay Archipelago (?). 
58. (€. secundum Cleve, Diat. f. the Sea of Java 1873, p. 10, Pl. I, 
f,14a,b; Leuduger-Fortmorel, 1. c. p. 37; de Wildeman, |. c. p. 134; Van 
Heurck, Synops., Pl. 82, f.5; C. curvisetum Cleve, Pl. f. the Ind. Ocean 
and the Malay Archipelago 1902, 
p. 18 and p.55, non Cleve, in 
Kanonbaaden Hauchs Togter, Kj6- 
benhavn, 1889, p.55 with fig. 
Professor Cleve supposes 
(in his last paper (1.c.1902, p.55)) 
that the Indian C. secundum is 
the same as C. curvisetum from 
the Temperate Atlantic, but I can 
not enter upon this opinion, as 
the spores of C. secundum figured 
by Cleve himself (1873, Pl. Il, 
f. 14a) are rather different from 
the spores of C. curvisetum (see 
Gran, Protophyta, Pl. II, f. 22). 
Q (rr) — 3 (r) — 4(rr) — 5 (rr) 
— 6(rr) — 10(r). 
Area: Malay Archipelago. 
59. €. siamense Ostf. n. sp. 
Chains straight, about 50 
broad; valves circular; fora- 
mina lanceolate; hoop at least 
a third part of the cell; chro- 
matophores two, close to the 
valves; awns all alike, rather 
robust, undulated; the one 
about in the sagittal plane, the 
other diverging at a nearly Fig. 17. Chaetoceras siamense Ostt., 
right angle. Chain in front view, cell in side view (7°). 
