XXVIl] ODONTOPTERIS 655 



Pinnules often occur on the main rachis, and in some species the petiole 

 bears modified pinnules which are larger than the ultimate segments of 

 the pinnae and in some cases Cyclopteroid in shape. The pinnules are 

 traversed by numerous dichotomously branched veins; if a midrib is 

 present it dies out in the basal part of the lamina. In some species 

 (genus Mixoneiira) pinnules of the Neuropteroid type, characterised by a 

 well-defined midrib, occur in association with typical Odontopteroid 

 pinnules on the same pinna. 



The species represented in fig. 364, C, D, from the Middle 

 Coal-Measures of Barnsley, Yorkshire, illustrates the form and 

 venation of the Odontopteris type of pinnule. Another species, 

 0. Reichiana Gutb.', is also recorded by Kidston from the Lower 

 Coal-Measures of Lancashire. Some unusually good specimens 

 of the type-species of the genus Odontopteris minor, Brongn., 

 have been figured by Zeiller'' from the Coal-Measures of Blanzy 

 (fig. 365) which show the dichotomy of the main axis and the 

 occurrence of Aphlebiae on the petiole. The late Dr Weiss* 

 divided Odontopteris into two sections, Xenopteris and Mixo- 

 neura, the pinnules of the former having the form shown in 

 fig. 364, D ; while in species of the latter sub-genus some of 

 the pinnules are identical in form and venation with those of 

 Neuropteris except that they are attached by the whole breadth 

 of the base. Zeiller* employs Mixoneura as a generic designa- 

 tion. In an American species 0. Wortheni Lesq.° the pinnules 

 bear numerous hairs like those on some species of Neuropteris 

 (fig. 373, p. 570). The large size of the fronds of Odontopteris sug- 

 gested to Weiss* that they were borne on the stems of tree-ferns, 

 but Grand'Eury's' examination of specimens in the Coal-beds 

 of central France led him to picture the plant as bearing a tuft 

 of leaves on a short subterranean stem. Renault and Zeiller', 

 on the other hand, obtained evidence in the Commentry Coal- 

 field of fronds borne on elongated stems which grew on the 

 ground and were supported by stronger plants. Stur» was the 

 first to suggest that Odontopteris should be excluded from the 



1 Kidston (89) p. 409. 



2 Zeiller (06) Pis. xix.-xxii.; (00^) p. 100, fig. 73. * Weiss, C. E. (70). 

 « Zeiller (06) p. 90. » Lesquerenx (80) A. p. 131 ; Weiss (70). 



« Weiss (69) p. 37. ^ Grand'Eury (77) A. PI. A. 



8 Renault and Zeiller (88) A. p. 219. » Stur (84). 



