ICI 3« No. 8. JAPANESE DIATOMS. 



between the terminal horns are also subject to certain variations. In the 

 narrow, elongated frustules they start patently dircctl}- from the corners 

 of the valves, and bend gradually upwards until the\- run parallel with 

 the axis of the chain. In more complanate, broader frustules they diverge 

 more widely, and are bent in an S-shaped curve. 



The suture lines of the girdle- band, seen from the flattened side of 

 the frustule, are always convex towards the foramen. 



Loc. OtaruBay; Echigo Prov. ; Misumi (Yendo) Enoshima (Schröder). 



Chaetoceras Lorenzianum Grun. 



Grunow: 1863, p. 157, PI. 5, fig. 13. — Van Heurck: 

 1880—85, Pi. 82, fig. 2. — Cleve: 1897a, p. 21, PI. 1, figs. 

 13 — 15. — Gran: 1906, p. 76, fig. go. — Schröder: 1906, 

 p. 335. — Okamura: 1907, p. 93, PI. 4, figs. 38, 39. — Do.: 

 191 1, p. 7, PI. XI, fig. 31. 



= C. ceUulosiim Lauder. 1864, p. 78, PI. 8, fig. 12. 

 Okamura's latest paper (191 1, I. c.) illustrating a spore-bearing chain 

 of C. Lorenzianum Grun. endorsed Cleve's observation (1897 a, 1. c). 

 Dicladia capreolits Ehr. and D. japonica Pant, are reported from 

 fossil Diatoms of Japan. We are inclined to approve the view that all 

 the species described under the genus Dicladia belong to the resting- 

 spores of Chaetoceras. The two fossil species must therefore be related 

 to certains forms of Chaetoceras. After consulting all the literature con- 

 cerning Dicladia, we found it impossible to decide whether there exist 

 other recent species with »Dicladiay^ spores than the present one and 

 the arctic Ch. Mitra, and perhaps the little known species of Castra- 

 cane, Ch. Dicladia. Cfr. Karsten, 1905, p. 119, Taf. XVI, fig. 2. We 

 will not venture, therefore, upon further discussion of these fossil forms, 

 but simply mention them here as they may have something to do with 

 the Chaetoceras flora of Japan. 



Loc. Boshu Prov. (Okamura). Misaki (Yendo). Enoshima; Akashi; 

 Formosa Channel (Schröder). 



Sect. 4. Cylindrica Ostenf. 



Chaetoceras teres Cleve. 



Okamura: 1907, p. 94, PI. 4, figs. 53 & 54. 

 = C. Willeit Y'endo: 191 i . 

 Okamura reports the above-named species from Boshu Prov. but 

 with some hesitation. The illustrations he has given are too incomplete 



