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hering organ occurs in Microdictyon Velleyanuvi Decne. = Jkf. 

 umbilicatum Zanard.; and also, I myself ascertained its existence 

 in Microdictyon umbilicatum Zanard. collected at Gulf of Naples 

 and sent from late Prof. Fn Schmitz. Now, by putting aside 

 the common character, i. e. possession of tenaculum, from Rhipidi- 

 phyllon and Microdictyon^ t;he former differs simply in its having 

 two kinds of cells, viz. those forming the main veins'ancl veinlets, 

 as well as non-umbilicated habit. I am really in accordance with 

 Heydrich's view in so far as the difference of Ripidi phyllon from 

 Anadyomcne is concerned, but, it seems to me rather weak to 

 separate the former genus from Microdictyon, simply by the 

 differences just spoken of. If existence of the present genus be 

 allowed, it should stand between Microdictyon and Anadyomcne, 

 and may be said to be more allied to the former than to the 

 latter. At any rate, here I have described the plant in question 

 provisionally under the genus Rhipidiphyllon. 



Plate XXX. Fig. I ： frond of Rhipidiphyllon retictdahtm 

 {As ken.) J-leydr. y -. ― Fig. 2 ： lower portions of two fronds 

 uniting to each other by ramuli, や. 一 Fig. 3 : middle portion of 

 the frond, ― Fig. 4 ： upper margin of the frond showing free 

 ends of ramuli and tenacula, ― Fig. 5 : lateral margin of 

 frond, showing the main veins and tenacula, や. 一 Fig, 6 : basal 

 portion of frond, ― Fig. 7 and 8 : adhesion of cells by 

 tenaculum. 



