PLATE VII. 



A. DICTYOTA, page 39. 



Fig. 1, D. dichotoma; the natural size. 2, sorus, on 

 a small portion of the frond. 3, vertical section of 

 the same. 4, spore, containing four sporules. 5, 

 fragment of the frond with scattered spores ; magni- 

 fied, 



B. TAONIA, page 38. 



Fig. 1, T. Atomaria ; the natural size. 2, portion of 

 the frond, showing spores in bands and scattered. 

 3, section of the frond with spores in situ ; mag- 

 nified. 



C. STILOPHORA, page 39. 



Fig. 1 , S. rhizodes ; the natural size. 2, fragment of 

 the frond, with sori. 3, cross section of frond and 

 sorus. 4, spore and filament or paranema. 



D. DICTYOSIPHON, page 40. 



Fig. 1, D.fceniculacens ; the natural size. 2, portion 

 of the frond, with scattered spores. 3, spore. 4, 

 cross section of a younger portion, and 5, of an 

 older portion, of the frond. 6, cellular tissue from 

 the interior of the same ; all magnified. 



