231 
Arber . — On the Past History of the Ferns . 
Palaeozoic period. Even in the truly Mesozoic floras, the only example 
which can be put forward as a possible representative of this group is the 
genus Sagenopteris , and even here the case cannot be said to be proved. 
In conclusion I would express my thanks to Dr. Scott for several 
suggestions embodied here, and for an opportunity of discussing these 
questions with him in some detail. 
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