156 APvï. 12. K. YENDO. 



never a coustunt character and is accidental. It is most frequent- 

 ly found in those plants which live on rocks at low-tide mark 

 fonting open seas. 



Numerous sterile cryptostomata are found throughout the 

 whole of the frond except in the basal cylindrical portions. 

 They are globular in shape, situated just below the cortical layer, 

 with a communicating opening through the latter. Hairs are 

 given off from the bottom of the cryptostoma and extrude through 

 the opening above the surface of the frond. In dried specimens 

 the hairs appear as inconspicuous white specks on the dark 

 brownish frond. 



The filiform type has a scutellate root a few mm. in diameter, 

 with one or more shoots starting from the same root. The 

 stem is cylindrical measuring l.-l.o mm. in diameter and ramifies 

 subregularly dichotomously with acute axils. The segments are 

 cylindrical or terete, more or less compressed, and broadened at 

 the point below each axil. They are similar in size and shape 

 everywhere in a frond, except the ultimate ones which are much 

 thinner and shorter. As the apical segments are pointed in this 

 type, the slit-like depression found in those of the foliose type, 

 now appears as an inconspicuous excavation. The substance of 

 the frond is cartilaginous and the colour is dark brown while in 

 the water, but turns black when exposed to the air. The total 

 height of a frond often reaches 15 cm. Cryptostomata are 

 wanting in this form. 



It is quite common to iind a branch of the foliose type in 

 a part of a filiform frond. The foliose branches may be near 

 the basal portion or at the middle of a filiform frond, and in 

 most cases several of them occur close to one another in the 

 same individual (PI. II, fig. 3). This is due to the extraordi- 



