― io6 ― 



In the younger portion of fronds, the intermediate cells are often here- 

 and there interrupted ； but in older portions, at least one layer of 

 til em is always present and even 4 or 5 layers in the marcrinal 

 portion. The cell-contents are somewhat poorer in these cells than 

 those in epidermis. Paranemata are always present. 



" Tetrasporanoia are spherical, only one or two being found 

 scattered at the beginning, but afterwards more and more collected 

 ■nto irrep-ularly oblong or linear sori, which are 2-4 mm. lonu or often 

 much lon;rer. The sori are scattered over both surfaces, leaving 

 sterile the narrow marginal linear and oasis-like patches of variable 

 breadth. Tetraspores appear under the microscope roundish or 

 polvp'onal from mutual pressure. Oogonia also collected into 

 roundish, dot-like sori, in which the spores radiate above the surfaces 

 of the frond. They are very densely scattered over the frond, almost 

 leaving no sterile marg-inal line. Both kinds of sori are elevated above 

 the surface of the frond. The sori of tetrasporan^-ia are much larrer 

 than those of oogonia. 



"Colour dark- yellowish-brown when recent, becoming very opaque 

 in older portions. On clryinp- the plant becomes almost blackish, the 

 brown colour being preserved only in younger portions. Substance 

 thick, coriaceous, thin and membranaceous only in the upper portion." 

 ― Okam. I.e. 



Hab. ： On rocks between tide-marks ； Pro vs. Tosa, Saga mi, 

 Boshyu, Kaclzusa, Isl. Niijima. , 



PL. XXIII, ngs. 1-6. Fig. 1 : Pachydidyon coriaccmn (Holm.)' 

 Okam. bearing" sori of tetrasporangia, \, ― Fip^ 2 : prowing apex of 

 frond, ―. 一 tip-. 3 ： terminal portion of frond, bearing tetrasporic 

 sori, -. — Fig. 4 : tetrasporan ゾ ia, — Fig. 5 : terminal portion of- 

 frond bearing sori of oospores, -ト. 一 Fig. 6 : sori of oospores, 



