120 

 RIELLA: 





Fig. 242. A, Riella halopluhi (left). B, R. pnrpureospora (right). The sectors 

 in the main figure (A + B) are as follows (enumerated clockwise, beginning 

 at A): sclerine, optical section; part of proximal (?), tenuitatiferous (?) face; 

 part of distal (?) face; sclerine, optical section; part of jiroximal (?), tenuitati- 

 ferous (?) face; part of distal (?) face. In the lower left-hand detail figure 

 tentative interpretations of the sclerine stratification in R. halophila are ex- 

 hibited. The lower right-hand detail shows an outline of the sclerine strati- 

 fication in R. purpiireospoi'd (the second layer from below should have been 

 blackened in, not dotted); the ()L-pattern is due to reticuloid arrangement 

 of the 'sexinous' (cf. endosexinous) elements in the third layer from below. 



