474 Bower. — Studies in the Phytogeny of the Fiticales. 
as a dermal covering. The sori resemble those of Metaxya in their large 
area and in their position, and in the presence of numerous hairs scattered 
among the sporangia. But the latter have thin and long stalks and an 
interrupted annulus, while the sorus appears to be of the mixed type. 
Notwithstanding that Neocheiropteris does not provide so convincing 
a link of connexion as was anticipated, the opinion may still be held, and its 
validity tested by further observations, that there is a natural relation 
between Neocheiropteris or Phymatodes and Metaxya. A Fern modelled on 
the Metaxya- type with numerous perforations in the stele and leaf-trace, 
with scales in place of simple hairs, and with a mixed sorus and long- 
stalked sporangia with a vertical annulus, would inevitably be classed as 
a Polypodium. But all these would be natural progressive steps from the con- 
dition of Metaxya , such as are abundantly illustrated elsewhere. There is 
reason to believe that they may have been taken by forms derivative from 
the Metaxya- type. But so far we have succeeded in recognizing no 
intermediate forms which would link Metaxya definitely with such Polypo- 
dioid derivatives. Till the gap is closed by such links, the suggested 
relation cannot count as more than a working hypothesis. But it is 
an hypothesis which should stimulate further inquiry. 
Summary. 
i. Metaxya rostrata , Presl, which has currently been included in the 
genus Alsophila , as A. blechnoides , (Rich) Hk., should be retained as Presl 
placed it, viz. as the single species of a substantive genus. 
