— 21 — 



This species belongs to the subgenus Phaeoceras Gran, which has 

 numerous small chromatophores, also in the awns. 

 tO (r). 



Area: Red Sea, Malay Archipelago, South China Sea. 



57. C. Schmidtii Ostf. in Ostenfeld & Schmidt, Plankt. f. the Red 

 Sea, etc. p. 155, f . 8 ; ?C. Weiss flogii Cleve, Pl. f. the Indian Ocean and 

 the Malay Archip. p. 15 and p. 55, non Schütt. 



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. C. secundum Cleve, Diat. f. the Sea of Java 1873, p. 10, Pl. II, 



f: 14 a, b; Leuduger-Fortmorel, 1. c. p. 37; de Wildeman, 1. c. p. 134; Van 

 Heurck, Synops., PI. 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, KjÖ- 

 benhavn, 1889, p. 55 with fig. 



Professor Cleve supposes 

 (in his last paper (1. c. 1 902, 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. II, 

 f. 14 a) are rather different from 

 the spores of C. curvisetum (see 

 Gran, Protophyta, Pl. II, f. 22). 



2 (rr) - 3 (r) - 4 (it) - 5 (it) 

 — 6frr) - 10 (r). 



Area: Malay Archipelago. 



59. C. siamense Ostf. n. sp. 



Chains straight, about 50 fx 

 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. Chaetoce ras siamense Ostf., 

 right angle. Chain in front view, cell in side view (^). 



