312 THE EHJETIC PLANT NAIADITA. [^^^g- IQOI? 



EXPLANATION OF PLATE XIIL 



Fig. 1, Part of a stem of Naiadita lanceolata, Brodie, bearing a sporangium 

 and leaves. (X 2.) 



2. Pieces of stem of N. lanceolata, bearing leaves of various forms. ( X 2.) 



3. Small portion of stem of jY. lanceolata, vritb leaves more higbly mag- 



nified, (x about 6.) 



4. Sporangium of fig. 1. (X 10.) 



5. Part of a section of a sporangium, to sliow the wall and the contained 



spores. (X 180.) 



6. Part of a section of a sporangium, showing spore-tetrads. (X 180.) 



7. An isolated spore-tetrad, dissolved out from the sporangium by 



hydrochloric acid, and mounted in balsam. ( X 180.) 



8. A single spore seen edgewise, showing the marginal rim crossing the 



spore as a dark band. (X ISO.) 



9. A. single spore seen en face, surrounded by the marginal rim. (X 180.) 

 10. P^rt of a spore, showing the general tuberculation of the surface and the 



large peg-like tubercles of the rim. (x ISO.) 



Discussion. 



Mr. Steahan remarked that it was of much interest to know 

 whether this plant grew in fresh or salt water. The Authoress had 

 described it as being associated with EstJieria, but according to the 

 late Edward Wilson &Mr. Wickes it occurred in the same bed with 

 marine forms, such as Oardium rliceticum and Pecten valoniensis. The 

 interest lay in the fact that the NaiacUta-hed occupied about the 

 same horizon as certain thin bands recently observed in South 

 Wales. There some red and green marls of typical Keuper aspect 

 occurred above the Avicula-contorta Shales, and clearly indicated 

 a temporary recurrence of Keuper conditions long after the first 

 incursion of the Rhaetic marine fauna. 



Mr. H. W. Burrows also spoke, and Prof. Sollas replied on 

 behalf of the Authoress. 



