— 16 — 



With some hesitation I refer a form which I have seen in some of 

 the samples to the new described C. calvum Gl. or to C. fortissimum Gran 

 (Nyt Magaz. Naturv. Kristiania 1900, p. 122, PL 9, f. 25), those two spe- 

 cies only differing in the number of chromatophores. 



3 (rr) — 6 (it) — 10 (rr). 



Area: [of C. calvum] Malay Archipelago, [of C. fortissimum] coasts of the 

 Northern part of Norway. 



43. C. clavigera Ostf., n. sp. 



Cells solitary or two together, 8 — 10 ji broad, mostly broader 

 than long, awns of the one valve shorter and more clavate than 

 those of the other valve; the thickened distal part of the awns with 

 twisted striations and short spines. Valves elliptic. Chromatophore 

 single, in front. 



Fig. 11. Chaetoceras clavigera Ostf. (^-p). 



This very characteristic species seems most allied to C. simplex Ostf. 

 from the Caspian Sea. 



6(+). 



44. C. coarctatum Lauder, Trans. Mier. Soc. 1864, p. 79, P. 8, f. 8; 

 Cleve, Diat. f. the Sea of Java 1873, p. 9. Pl. II, f. 10 a, b, c; Leuduger- 

 Fortmorel, 1. c. p. 37 ; Cleve, Pl. f. the Red Sea p. 1032 ; Ostenfeld & Schmidt, 

 PI. f. the Red Sea, etc. p. 153; Cleve, Pl. f. the Indian Ocean and the 

 Malay Archip. p. 18 and p. 54; C. boréale, v. rudis Cleve, Phytoplankton 

 p. 20, Pl. I, f. 5 ; C. rudis Cleve, Atl. Plankt. Organisms p. 308. 



Chromatophores numerous, small. As Cleve (Pl. f. Ind. Ocean p. 54) 

 has stated, the chains are often set with vorticells. 



2 (rr) — 3 (rr) - 4 (rr) - 6 (rr) — 7 (rr) - 8 (rr) — 10 (r). 



Area: Tropical Atlantic Ocean, Mediterranean, Red Sea, Indian Ocean, 

 Malay Archipelago, Hongkong. 



45. C. compression Lauder, Trans. Micr. Soc. 1864, p. 78, PI. 8, 

 f. 6; Cleve, Diat. f. the Sea of Java 1873, p. 8; Leuduger-Fortmorel, 



I. c. p. 37; de Wildeman, 1. c. p. 133; Ostenfeld & Schmidt, PI. f. the 

 Red Sea, etc. p. 153; Cleve, Pl. f. the Indian Ocean and the Malay 

 Archip. p. 18 and p. 55 : C. Kelleri Brun, Espèc. nouvel!., Le Diatomiste 



II, Pl. XVII, f. 91, 92. 



