1913- ^^- ^- JAPANESE DIATOMS. 21 



= C. sp. Lauder: 1864. PI. 3, fig. 8. 



= C. fiirca var. nincrocorns Schröder: 1906, p. 351, fig. 15 

 — Okamika: 1907, p. 99, PI. 3, fig. 7. 

 ScHR()DKi; mentioned a Japanese form as a distinct variet)-, rank and 

 Okamura followed him. The size of the furcate setæ is variable accor- 

 ding to the individual, and is by no means so important as to entitle 

 to a distinct position as a variety. 



Loc. Shima Prov; Boshu Prov; Yosa Prov. (Okamura). Enoshima; 

 Akashi (Schr(")Der). Misaki; Misumi (Ykndo). 



Sect. 12. Brcvicatenaia. Gran. 

 Chaetoceras crinitum Schutt. 



Schutt; 1895, p. 41, fig. 12 a — d, — Ostenfeld: 1901, p. 298. 

 fig. 10. — Gran: 1906, p. 87, fig. 113 — Schröder: 1906. p. 337 

 (Nomen). — Okamura: 1907, p. 99, PI. 3, figs, i — 3. 

 We doubt Okamura's identification. The illustrations he has given 

 in the above-mentioned paper are too rough to show the characters, 

 and may be equally well applied to other species. 

 Loc. Boshu Prov. (Okamura). Enoshima (Schröder). 



Sect. 13. Curriseia. Ostenf. 

 Chaetocera.s secundum Cleve. 



Cleve: 1873b, p. 10, PI. 2, fig. 14. — - Ostenfeld: 1902, p. 

 239. — Vendu: 1905, p. 47, PI. XI, fig. 19. — Okamura: 1907, 

 p. 79, PI. 4, figs. 49—52. 



= C. carviseiiim Cleve: 1902, p. 18, 55 (non alior) 



'= C. curvisetuni Schr(")der: 1906, p, 337. 

 'Phe sterile forms of C. f^ecnndnm Cleve and C. curvisetum Cle\'e 

 so closely resemble one another that there has often been confusion with 

 regard to their specificlimits. Clevk himself, who has established both species, 

 once stated their probable identity. The resting-spores however, according 

 to the drawing by Cleve, 1. c, fig. 14, are different in the twospecies, 

 and there can be little doubt left as to their independent specific rank, Our 

 specimens lack spores, and Okamura also referred his plant to this 

 species without any comment on the spores. After comparative study 

 of C. cnrvisetum and ('. secimduni in the material from the Atlantic 

 Ocean, we are inclined to believe that the foramina are elliptical but slightly 

 narrowed in the middle in the latter, while they are more or less rhombic 



