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and thicker, and by the abrasion of the wing, the midrib changes 

 to the stem which ramifies wilh no definite order. All the seg- 

 ments are same in shape and other characters. They are lan- 

 ceolate, rolled up at the apices towards the ventral surface and 

 are furnished with minute pinnae or " Flankenaste ，， of German 

 writers, which appears like marginal teeth. Pinnae, which are of 

 endogenetical origin, incurve towards the ventral side and carry 

 similar pinnulse along their margins. 1 hey remain mostly short, 

 but sometimes grow up into segments similar to the rest. Thus, 

 the ramification is brought about by two ways, firstly Ly the 

 growth of pinnae and secondly by resette-like proliferations. Among 

 our specimens, I have seen some forms in which root-like processes 

 are emitted from marginal portion of an older lamina (fig. 5). 

 And in other case, I have detected a plantlet which has developed 

 itself into a separate individual by emitL : ng root-fibres from the 

 lower harmed end of the midrib of lamina (fiig. 4). From these 

 instances, the alga seems to adhere to substratum by its parts 

 and not uncommonly to effect vegetative multiplication. 



Lamina is entirely destitute of cortication excepting the 

 thickened midrib, and consists of two layers of horizontal rows 

 of elongated, hexagonal cells which are derived from paired 

 pericentral cells disposed on both sides 01 the midrib. The height 

 of the cells of lamina measures 72-1 20 p. and we may count 

 about 150 cells between margins. Along dorsal median line of 

 limina, a row of deciduous hair-leaves is arranged, which are branch- 

 ed many times dichotomosly. The original lamina can always be 

 seen even in thickly corticated portion such as stem and branches. 



Tetraspovangia are formed in slightly altered pinnulse in 

 double rows along the ventral surface, being covered by two 

 so-called if cover-cells/' Pinndae which produce tetrasporangia are 

 lanceolate and simple or sparingly branched and are usually 



