138 FIL1CES. 



pteris, Gutb. l and Lonchopteris 2 . The former developes the nervation of 

 Ophioglossum, an uniform network of polygonal meshes; in the latter 

 there is also a distinct midrib, so that the habit is that of some recent 

 species of Pteris, Pt. aurita, for example. 



Of Mesozoic forms belonging to this group two series may be dis- 

 tinguished ; one of those in which the meshes of the network are all alike 

 and separated by nerves of equal strength, as in the species from the Coal- 

 measures just mentioned, the other of those in which nerves of unequal 

 development form by their anastomoses meshes of a higher and a lower 

 order, answering therefore to some extent to Mettenius' types, Anaxetum, 

 Drynaria, and Drynaria appendiculata. 



Of the first series the genus Sagenopteris, Presl, has the first claim to 

 notice. Sagenopteris rhoifolia, Presl, the best-known species, is peculiar to 

 the Rhaetic beds, and is found both near Bamberg and in Schonen 3 . A few 

 other species belong to the Lias and the Lower Oolite beds. At the 

 extremity of the long leaf-stalk is the lamina composed of four pinnae 

 which spring from the same point. The ovate pinnae have a nervation 

 like that of Ophioglossum and show no trace of a median nerve. A 

 number of genera with similar nervation have been described by O. Feist- 

 mantel from the Lower Gondwanas (Trias) of India, from deposits in 

 Australia overlying the Coal-measures, and from South Africa 4 . Such 

 are Palaeovittaria with leaves of probably the same structure as those of 

 Sagenopteris, and forms with simple ligulate leaves like Gangamopteris 

 and the genus Glossopteris 5 , which is said by Feistmantel to be provided 

 with a median nerve ; lastly, the strange Belemnopteris with a simple 

 sagittate leaf-blade. The different attempts of authors to prove that 

 Sagenopteris has its place with Marsileaceae will be noticed in discussing 

 that group. 



From the second series of genera the Rhaetic form Thaumatopteris 

 Miinsteri, Gopp., may be selected for notice as the one with which we are 

 best acquainted ; many good figures of it are to be found in different 

 authors 6 . The deeply sinuate pinnatifid leaf-segments combine to form 

 a handsome palmate sympodial leaf-blade. Clathropteris, Brongn. 7 and 

 Dictyophyllum, Lindl. and Hutt. 8 are also from the Rhaetic beds, but 

 Dictyophyllum rugosum also occurs in the Oolite- of Scarborough. 

 Camptopteris, Presl 9 , with a handsome leaf like that of Thaumatopteris, is 

 peculiar to the Keuper. 



It remains only to notice in a few words those leaf-forms which can- 

 not be regarded as certainly belonging to the Ferns. One of them, the 



1 Goppert (1), 5 and 6, t. 3. * Brongniart (1), t. 131. 8 Zittel (1), p. 155 ; Schenk (3), t. 12 ; 

 Nathorst (2), t. 4, ff. 3-5. 4 Pal. Ind., sen xii, with numerous figures; O. Feistmantel (1), in. 



5 Schimper (2), p. 134. 6 Zittel (1), p. 137 ; Schenk (3) ; Nathorst (2) ; Goppert (1), i and 2, 



tt. 1-3. 7 Zittel (1), p. 138. Schimper (1\ t. 41, f. 22. * Schimper (1), t. 42, f. 4. 



