Plate I. 



Figs. I — 1). Amp/iinxt vahniioides. 

 1 and 2. Two forms of the I'roiitls, x Ca. 7. 

 3. A longitudinal section through a hiaiiching point : The cortical 



parts arround the genicula are not yet broken ott". Zeiss. 



'2 X BB. 



Fig. 4. Ainphiroa cretacea, End/. 

 A diagraniatic figure of a longitudinal section of a frond : the medullary 

 portion is hounded with a dotted line ; a conceptacle bulging out from 

 the cortical part. 



Figs. 5 — (). Amphiroa rigkla, Lainx. 

 5. A diagramatic figure of a longitudinal section of a frond ; six conceptacles 



are seen immersed in the cortical part. Zeiss. 2 x AA. 

 C. The geniculum of the same section more magnified ; the genicular cells 



are intertwixed at the middle portion of the geniculum. 



Figs. 7 — 9. Amphiroa epliednea, LamJc. ,-l. 



7. An apical part of a branch of the isolated form, x Ca. 2^. 



8. The same of the tuft form, x Ca. 2|. 



9. A portion of a longitudinal section of an articulus of the isolated form ; 



from fresh material, decalcified and fixed with chromic acid 4% sea 

 water solution. Zeiss. 2 X DD. 



Fig. 10. Amphiroa epltrdrtca, Lavil'. y. 

 An apical i>art of a branch, x Ca. 2|. 



Figs. 11 — -14. Amphiroa voiiafa. 



11. A Y>ortion of branch magnified : The terminal furrows and the 



transverse zones are clearly seen. 



12. A portion of a meridional section of an articulus : observe that the 



cortical layer is very thin. Zeiss. 4 x AA. 



13. A longitudinal section of the terminal ])ortion of a branch. The 



cellular arrangements are much disturbed at the furrow, and the 



