i9'3- 



Xo. 8. 



JAPANKSE DIATOMS. 



17 



C. Schiiiin Clevk (190 i b, p. 19). Judging from the observations we 

 have hitherto made of these species of Cleve's, we are strongly tempted 

 to include them as synonyms under the present species. 



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

 (Schröder). Yeddo Bay (Clkve). Misaki; Misumi (Yendo). 



Chaetoceras paradoxum Cleve. 



Cleve: 1873b, p. 10, PI. 3, fig. 16a. — Ostenfeld: 1902, 

 p. 237. — Okamura: 1906, p. 98, PI. 3, figs. 12 — 15. 



?= C. Lorenzîi Grunow: Van Heurck, 1880—85, PI. 82 

 bis, fig. 9. 



Our acquaintance with this species is not very complete. Cleve's 

 original diagnosis of the species is not sufficiently clear to separate it 

 from (\ affine Lau])ek. Okamura, however, 

 referred a specimen from Shima Province to 

 the present species. He delineates his specimen 

 with specially thickened cell-walls, and deeply 

 constricted girdle-bands. We found similar 

 specimens in the material from iVIisumi, and 

 with spores. Comparing it with C ö//7'//t; Lau- 

 der, in our specific conception, from various 

 localities, w^e find our plant quite distinct from 

 Lauder's, and venture to refer it to the pre- 

 sent species. 



The unusually thickened cell-wall char- 

 acterizes the species to some extent; but the 

 resting-spores specify it more sharply. The 

 spore-walls are as thick as the frustular walls, and there is a deep 

 groove in the latter near the point of contact with the secondary valve 

 of the spores. The shape of the spores, as also the spines on them, 

 show a great resemblance to C. affine Laud. 



Okamura illustrates a specimen with a thick cell-wall and deeply 

 grooved girdle-band under C. affine (1. C, fig. 4, c); but it probably be- 

 longs to the present species. 



Loc. Shima Prov. (Okamura). Misumi (Yendo). 



9. Chaetoceras para- 

 doxum Cleve. 

 a. Frustules with resting- 

 spore. From burnt pre- 

 paration. X 360. 

 /;. The deep girdle con- 

 striction near the point 

 in contact with spore. 

 Highly magnified. 



Vid.-Selsk. Skrifter. I. M.-N. Kl. 1913. No. 8. 



