234 16 
With some hesitation I refer a form which I have seen in some of 
the samples to the new described C. calvwm Cl. or to C. tortissimum 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(rr) — 10 (rr). 
Area: [of U. caluum] Malay Archipelago, [of C. tortissimwm] coasts of the 
Northern part of Norway. 
43. (. elavigera Ostf., n. sp. 
Cells solitary or two together, 8—10 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. (42°), 
This very characteristic species seems most allied to C. simplex Ostf. 
from the Caspian Sea. 
6 (+). 
44. (. coaretatum Lauder, Trans. Micr. Soc. 1864, p. 79, P.8, f. 8; 
Cleve, Diat. f. the Sea of Java 1873, p.9. Pl. II, f. 10a,b,c; Leuduger- 
Fortmorel, 1. c. p. 37; Cleve, Pl. f. the Red Sea p.1032; Ostenfeld & Schmidt, 
Pl. f. the Red Sea, ete. p. 153; Cleve, Pl. f. the Indian Ocean and the 
Malay Archip. p. 18 and p.54; C. boreale, 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, thé chains are often set with vorticells. 
Q(rr) — 38(rr) — 4(rr) — 6 (rr) — 7(rr) — S(rr) — 10(r). 
Area: Tropical Atlantic Ocean, Mediterranean, Red Sea, Indian Ocean, 
Malay Archipelago, Hongkong. 
45. €. compressum Lauder, Trans. Micr. Soc. 1864, p. 78, Pl. 8, 
f. 6; Cleve, Diat. f. the Sea of Java-1873, p. 8; Leuduger-Fortmorel, 
l.c. p. 37; de Wildeman, 1. c. p.133; Ostenfeld & Schmidt, Pl. f. the 
Red Sea, ete. p. 153; Cleve, Pl. f. the Indian Ocean and the Malay 
Archip. p. 18 and p.55; C. Kelleri Brun, Espéc. nouvell., Le Diatomiste 
Il, Pl. XVII, f. 91, 92. 
