HOW TO KNOW THE SEAWEEDS 



107a Tetrasporangial conceptacles with many small pores formed by 

 the transformation of rows of cells into gelatinous plugs in the roof 

 of the conceptacles. Figs. 143, 144 Lithothamnium 



Fig. 144. Lithothamnium sp. 



Diagrammatic represen- 

 tation of a tetrasporangial 

 conceptacle to show the 

 several pores in the roof 

 and the form and position 

 of the zonate tetrasporan- 

 gia, X 40. 



Figure 144 



107b Tetrasporangial conceptacles opening by a single, relatively large 

 pore. Fig. 145 108 



108a Tetrasporangia borne over whole floor of conceptacle 



Goniolifhon 



108b Tetrasporangia marginal within the conceptacles, the central area 

 of the floor occupied by paraphyses. Fig. 145 Lithophyllum 



Fig. 145. Lithophyllum sp. 



Diagrammatic represen- 

 tation of a tetrasporangial 

 conceptacle to show the 

 single large pore in the 

 roof and the marginal posi- 

 tion of the zonate tetraspo- 

 rangia with a group of 

 paraphyses occupying the 

 central area of the con- 

 ceptacle floor, X 40. 



Figure 145 



112 



