1 24 DICTrOPHYLLTJM:. 



AS regards the form of tlie frond, with Matonia peotinata, E. Br., 

 but the soral characters and the form of the leaf point rather 

 to a comparison with the genus Bipteris. Dvpteris ' is a tropical 

 •Indo-Malay type represented at the present day by a few species, 

 which have usually been placed among the Polypodiacese, but the 

 sporangia do not appear to be typically polypodiaceous, and the 

 -genus is clearly an isolated type of somewhat uncertain position. 

 Eaciborski ^ has suggested the new family term Protopolypodiaceae 

 for the reception of a fertile Bietyophyllum leaf characterized by 

 naked sori, consisting of a few sporangia with an oblique annulus, 

 characters which are found also in the recent species of Bipteris. 

 It is proposed to discuss more fully elsewhere the systematic 

 position of the recent genus, but such evidence as we at present 

 possess favours the view that Bietyophyllum and Protorhipis are 

 •closely related to Bipteris, and constitute Mesozoie members of 

 & group of ferns now barely represented, buj; in former times 

 widely distributed. It may be convenient to emphasize the 

 affinity of Biotyophyllumi with Bipteris, and the isolated position 

 ■of both these genera and Protorhipis, by placing them provisionally 

 in a separate family, which we may designate the Dipteridinse, 

 using in a wider sense a term already employed with a more 

 restricted meanina;. 



39,224. PI. XIII. Pig. 3. 



Portions of two pinnte which are so placed as to suggest their 

 proximity to a common raohis towards which they are converging. 

 The whole frond probably had a habit simUar to that of Matonia 

 peotinata, Cheiropteris, Laccopteris, and other genera. The single 

 segment represented in the figure is given off practically at right 

 angles from the axis of the pinna, and represents a portion of 

 a long and narrow segment with irregularly dentate or undulating 

 margins, similar to the form of leaf named by Zigno Bietyophyllum 

 Beclcenbyi. The venation characters are fairly well shown in the 

 figured specimen. Labelled Phlelopteris Phillipsii in Bean's MS. 



Gristhorpe. Bean Coll. 



1 Engler & Prantl (99), p. 202, fig. 108. Vide also Beddome (66), pi. Ixxx. 



2 Eaciborski (91), p. 8. Vide also Patonie (99), p. 86. 



