PLATE XVIII. 



A. PHYLLOPHORA, page 142. 



Fig. 1, P. rubens ; the natural size. 2, a nemathe- 

 cium. 3, filaments from the same. 4, tubercles. 

 5, spores from the same ; all magnified. 



B. GYMNOGONGRUS, page 145. 



Fig. 1, G. Griffithsi<B ; the natural size. 2, part of a 

 fertile branch with nemathecium. 3, section of ne- 

 mathecium. 4, chained tetraspores from the same ; 

 all magnified. 



C. FURCELLARIA, page 146. 



Fig. 1, F. lumbricalis ; the natural size. 2, cross sec- 

 tion of a portion of the frond, showing tetraspores 

 imbedded among the filaments of the periphery. 3, 

 a tetraspore attached to a filament ; all magnified. 



D. POLYIDES, page 146. 



Fig. 1, P. rotundus ; the natural size. 2, section of 

 part of the frond, and of one of the warts. 3, favel- 

 lidium from the wart. 4, a spore. 5, a tetraspore 

 from another specimen ; all magnified. 



