may, 1907.] OKAMTJRA.—CHAETO. & PERAGAL. OF JAPAN. 97 



This species, as it seems to me from our specimens, is per- 

 haps the same as C. Schiittii Cleve, as Prof. Gran remarks in 

 his Diatomaceae, 1905, p. 81. I have found that all the spines 

 lie on the sagittal-longitudinal plane as is shown in Fig. 4 a. 

 As I have mentioned under C. Ralfsii I have found that the 

 terminal horn of this species is similarly constructed as in C. 

 Ralfsii ; that is, it is quadrangular and has very minute dot-like 

 teeth along the ridges. 



Breadth of the cell measures 26 it in the specimen shown in 

 Fig. 4, and the thickness and breadth, Wp. and 33 ti respec- 

 tively in that shown in Fig. 4 a. 



Loc. in Jap. : Tateyama in the Pro v. Boshyu (June, 2, 

 1906) ; Shinoshima in Prov. Owari (Aug., 1906) ; Cape 

 Goza in Prov. Shima (Aug., 2, 1904). 



19. C. Ralfsii Cleve in Schroder, 1906, p. 352, f. 16 ; Cleve 

 Diat. of Java, 1873, p. 10, PL III, Fig. 15. ? 



Loc. in Jap. : Cape Goza in Prov. Shima (Aug., 2, 1904) ; 

 Enoshima in Prov. Sagami (Schroder). 



Schroder illustrates in his " Beitr. z. Kenntnis des Phyto- 

 planktons warmer Meere," p. 352, f. 16 Chaztoceras Ralfsii Cleve, 

 (I have no facility to refer to p. 251 where the explanation of 

 this species may perhaps be given) which much differs from the 

 original figure given by Cleve in his " Examination of Diatoms 

 found on the Surface of the Sea of Java" p. 10, PI. Ill, Fig. 15. 

 I have identified my material after Schroder's illustration, and 

 if his figure really represents Ch. Ralfsii, the necessary conclusion 

 might be that Cleve's Ch. Ralfsii is nothing but Ch, afRni Lauder. 



Struck by Schroder's representation I entered into compara- 

 tive study of terminal horns of Ch. Ralfsii and Ch. afhne and 

 found that both are similarly constructed as are shown in our 

 Figs. 4 b and 6 c. This character is at variance with Cleve's 

 remark which says " this species {Ch. Ralfsii) resembles Ch. 

 afhne Lauder, but the awns are dissimilar." The possession 

 of dot-like spinules on terminal horns being common to both 

 species, the only difference between those of the species related 

 is the degree of curvature. 



