may, 1907.] OKAMTJRA.-CHAETO. & PERAGAL. OF JAPAN. 95 



with a chain of Ch. compression in which four filaments of R. 

 intracellular is were observed, each being inserted between two 

 cells. I thought that it was accidentally so placed ; but when 

 I met with another chain of that species similarly infested in 

 the same sample, I came to consider that there should exist 

 some relations between the two organisms. Though there are 

 plenty of chains of Ch. compressum, they are not all infested 

 with this parasite nor does every foramen of each chain ; for 

 there must be certain coincidence between the thickness of the 

 parasitic filament and size of foramen of the host. 



As far as we know we must conclude that R. intracellulars 

 is either endo- or ecto-parasite which has probably certain rela- 

 tions of nutrition with diatomaceous organisms such as Rhizo- 

 solenia and Ch. compressum and perhaps still other ones. 



In our specimens represented in Figs. 8—10, breadth, length 

 and thickness of cells of Cha^toceras measure 5p, 5 p. and 2.5 p 

 respectively ; in Fig. 11, breadth, 22 ft. 



Section 6. Protuberantia Ostf. 



13. C. didymum Ehr. v. genuina Gran. PL IY, Fig. 48 a-c. 

 Gran, Diat., 1905, p. 79, Fig. 94. ? Btw., Micr. Journ. Vol. 



IV, 1856, PI. VII, Figs. 3-7. 



The specimens before us are perhaps young ones which have 

 close resemblance to the figures given in Btw. 1. c. PL VII, Figs. 

 3-7. 



Loc in Jap. : Prov. Tosa. 



Breadth and length measure 20 fi and 7.5 p. respectively in 

 the specimen shown in Fig. 48 h. 



14. C. didymum v. anglica (Grun. ) Gran. PL IV, Figs. 44-47. 

 Gran, Diat., 1905, p. 80, Fig. 95.- C. longicrure (CI.) Ostf. u. 



Schm. Red Sea, p. 154 ; Ostf. Faroes, 1903, p. 576.— C. didymum 

 var. longicruris Cleve, Treatise, 1897 a, p. 21, PL I, Figs. 11, 17. 



Loc. in Jap. : Cape Goza in Prov. Shima (Aug., 3, 1904 ; 

 Feb., 3, 1904). 



Breadth and length measure 10 // and 5-14 ft respectively in 

 the specimen shown in Fig. 44. The specimen represented in 



