FILICES. 153 



the annulus, which is distinctly formed in each case, would afford an ex- 

 cellent means of distinguishing them. It is true that Williamson *, for 

 example, and Carruthers 2 have figured a good many sporangia in sections 

 from English calcareous nodules, which they consider to belong to Gleiche- 

 niaceae or Hymenophylleae. I possess a variety of sections through these 

 sporangia in which at first sight we fancy that we see an evident circular 

 annulus. But if we happen to light upon a surface-view of these objects, we 

 see that the wall is everywhere of the same structure, and that every section 

 therefore in whatever direction it is made would show an illusory annulus 

 transversalis ; there is nothing therefore which compels us to regard them 

 as anything else but sporangia of Marattiaceae, especially when we know 

 how generally the latter are distributed through the groups of the Palaeozoic 

 formations. The best-known example from the Coal-measures is certainly 

 the fern-leaf figured by Zeiller 3 as Hymenophyllites delicatulus, Stbg. 

 Here there does really seem to be a transversal annulus, as appears 

 especially from the side-views given in Zeiller's figures 4 . It is true that 

 I have never myself seen sporangia in this position in the original specimens, 

 which the author demonstrated to me in the kindest manner, probably 

 because the shortness of the time at my command did not admit of a 

 thorough study of the slab ; but I carried away with me the general 

 impression that the facts had been correctly interpreted and that no other 

 explanation of the pictures was possible. We need not indeed go into the 

 question whether we are justified in calling the leaf Hymenophyllites ; it is 

 in favour of this determination that the sporangia which are no longer in 

 situ lie in groups in front of the extremities of the nerves of the tip of the 

 leaf; there is no trace of the characteristic thorn-shaped placenta or of the 

 cup-shaped indusium. Another form described as of the same group, 

 Hymenophyllum Weissii 5 from Saarbriicken, is to my mind more than 

 doubtful ; its sporangia are unknown, and I have been unable to satisfy 

 myself from the specimens in the Museum at Strassburg that the character 

 of the sori is as described by the author. Heyer 6 also, who had the 

 specimens in the. Goldenberg collection before him, was not more suc- 

 cessful than myself. The same remark applies also to Hymenophyllites 

 Humboldti, Gopp., and Trichomanites Beinerti 7 , as well as to the genus 

 Palaeopteris, of which Schimper figures the fruiting heteromorphous leaf- 

 segments 8 . In these also the structural details of the fructifications, which 

 are declared by the author to be two-lobed indusia, cannot be certainly 

 determined. 



While it is thus scarcely within our power to prove the existence of 



1 Williamson (1), VIII, t. 7. a Carruthers (6), p. 3. 3 Zeiller (7), t. io,ff. 23-32. * Ibid., 



ff- 30,31- 5 Schimper (1), t. 28, ff. 4, 5. ' Heyer (1), p. 394. 7 Goppert (1). 8 Schimper 

 (1), t. 36, and Zittel (1), p. 113. 



