XXVIl] NEUROPTERIS 567 



placed in this generalised group. Renault ^ pointed out that 

 the petioles of Neuropteris fronds from Autun had the anatomical 

 features of Myeloxylon (petiole of Medullosa). Since Kidston's 

 important discovery of seed-bearing pinnae of N. heterophylla, 

 Grand'Eury^ has recorded the association of Neuropteris fronds 

 with seeds in French Coal-fields. By some of the older authors 

 Neuropteris was compared with Osmunda because of a similarity 

 in venation. In the frequent dichotomy of the frond and 

 in the occurrence of pinnules on the rachis, Neuropteris closely 

 resembles Odontopteris^ : there can be little doubt as to the 

 close relationship of the Pteridosperms possessing these two 

 types of foliage. Neuropteris may be defined as follows : 



Fronds reaching a considerable size, probably in soma cases a length of 

 10 metres*; bi- or tri-pinnate; the rachis may be dichotomously branched 

 (figs. 354, D ; 370) ; both rachis and petiole bear single pinnules, those on 

 the latter frequently differ from the normal leaflets in their larger Cyclo- 

 pteroid laminae (fig. 370). Pinnules entire, rarely slightly lobed, broadly 

 linear, attached by a small portion of the base, which is usually more 

 or less cordate. In #. Grangeri Brongn. the pinnules are attached by 

 a short pediceP. The midrib always dies out before reaching the blunt or 

 pointed apex of the lamina abd gives off at an acute angle numerous 

 secondary veins characterised by their arched course and repeated forking. 



Potoni6 describes the secondary veins of the pinnules of 

 Neuropteris pseudogigantea^ as occasionally anastomosing, a 

 feature which may be regarded as a step towards the reticulate 

 venation of the closely allied genus Linopteris. 



Eenault'^ described some petrified pinnules of Neuropteris 

 in which the mesophyll shows a differentiation into upper 

 palisade tissue and lacunar tissue below; the lower epidermis is 

 infolded at intervals where grooves (probably stomatal) occur 

 like those on the leaves of an Oleander {Nerium oleander). 



The rachises of Neuropteris fronds are described by Grand'- 

 Eury under the generic name Aulacopteris^. 



1 Renault (76). 2 Grand'Eury (08). ' White (99) p. 128. 



* Grand'Eury (77) A. p. 122. » Zeiller (90) PI. xi. fig. 6. 



« Potoni6 (99) p. 113. ' Renault (82) A. Vol. in. ; Zeiller (90) p. 139. 



8 Grand'Eury (77) A. p. 105. 



