224 



THE BOTANICAL MAGAZINE. 



[Vol. XXXV. Xo. A-20. 



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A: Two spore-forming ells have di>ch:iiged a greater portion uf the contents. 

 B: A part of chain having a daughter-chain of 2 fnistules. The epitheca of the 

 fir.^t fnistule still remaining in the ruptured perizonium. C: Valve view of a 

 mother frustule with a daughter-chain. The axis of the daughter-chain is per- 

 pendicular to the axis of the mother one. D: Front view of a mother-chain with 

 one auxospore and one daughter-chain. 



