CHLOROPHYCE.E 159 



of a membrane of the form of a watch-glass. 

 This cell then proceeds to grow out from its parent 

 cell, and assumes a similar shape. The process 

 is then repeated, and *by this means a thallus is 

 produced, generally with irregular branching, but 

 sometimes having the appearance of successive 

 dichotomous or verticillate branching from the apex 

 of each generation of cells. 



Dictyosphceria favulosa in its early state is an 

 irregularly globular mass of large cells (Fig. 47c), the 

 interior of the mass becoming hollow with its growth. 

 It eventually bursts, and the thallus is then ir- 

 regularly lobed. It consists of numerous cells in 

 several layers, all of these being bound together by 

 sucker-like holdfasts, short where the cells are closely 

 packed, and long-stalked where they are more loosely 

 aggregated. There are remarkable internal spines 

 projecting from the cell-membrane into the cell- 

 cavity (Fig. 47 A). D. scricea has a different arrange- 

 ment of holdfasts, but the main points of structure 

 are the same. Wille describes the origination of 

 the cells of Dictyosphceria within a mother cell. This 

 may be the case, but an examination of many early 

 stages of D. favulosa does not bear it out. However, it 

 would be in harmony with what is known of Valonia. 



The placing of Elastophysa among the Valoniacece 

 is uncertain. The plants are green, very irregular, 

 much lobed cells with long colourless hairs. It is 

 certainly multinucleate, but its reproduction is un- 

 known, and its Vegetative characters inadequate for 

 determining its true position. 



Siphonocladus is a simple, minute, multicellular 



