( 6 ) 
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Antheridia and Tetraspores. By Edward Pbkceval "Wright, M.A., M.D., 
F.L.S., F.R. C.S.I. ; Professor of Botany in the University of Dublin. (With 
I Plates XII. and XIII.) 
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22. — Explanatory Notes and Discussion of the Nature of the Prismatic Forms of a Group 
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