70 



erigiUir el fit fere cucuUatim involuta, marginibus siirsum hianlibus (I.e. fig. 42)". 

 The celebrated author has not perceived Hiat the leaf-like frond arises by splitting 

 of a globular vesicle, but his fig. 41 seems to represent just the state where the 

 split is formed. When the frond grows older, numerous rhizines are formed from 

 the cells in the lowest part of the frond, which may result in the original basal 

 cushion becoming less distinct; it is however always evident that the cells in the 

 basal portion of the frond are situated in more than one plane. 



I'ui-jihijinpsis cocciiicu. A. yuuii^ iihiiil. slill luMiiisplu'rical. .V>(1:1. more dcveldpod pUnil with i'\i)aii(lt'(l 

 lamiiKi and s])oie-mother cells scattered over the frond. ;!40:1. C, lower part of older ])lanl : il was nol 

 plane, hill llie borders were curved somewhat backwards. :i4(l : 1. IJ, basal portion of frond showing the 



rliizincs. fi.iO : 1. 



This [)lant offers an interesting analogy to the genus Monostroma among the 

 Chlorophijcece and the genus Omphalophyllum among the Phceophyced'. In Porphyra 

 naiadiim Anderson the frond also begins according to Hus (1902, p. 212) as a 

 parenchymatous cushion, but the later development is quite different from the 

 above described, the cushion producing from its surface hair-like projections which, 

 dividing in two directions, give rise to a monostromatic frond. 



The cell-divisions lake place in some measure uniformly over the whole 



