PLATE XXII. 



A. PTILOTA, page 159. 



Fig. 1, P. plumosa ; the natural size. 2, favella on its 

 peduncle, surrounded by involucral ramuli. 3, favella 

 removed. 4, ramulus bearing tetraspores. 5, a te- 

 traspore. 6, pectinated ramulus ; all magnified. 



B. MICHOCLADIA, page 160. 



Fig. 1, M. glandulosa ; the natural size. 2, ramulus 

 with favella. 3, favella. 4, ramulus with tetraspores. 

 5, a tetraspore ; all magnified. 



C. CERAMIUM, page 161. 



Fig. 1, C. rubrum; the natural size. 2, ramulus with 

 favellidium. 3, ramulus with imbedded tetraspores. 

 4, a tetraspore ; all magnified. 



D SPYRIDIA, page 166. 



Fig. 1, Jilamentosa ; the natural size. 2, fragment 

 with pedunculated favellae. 3, fragment with ramuli 

 bearing tetraspores. 4, a tetraspore. 5, a transverse, 

 and 6, a longitudinal, section of the frond ; magni- 

 fied. 



