FOSSIL PLANTS. 411 



3. Schizopteris proper, to which belong the species with a frond generally 

 laciniate, or cut in linear erect or curved divisions, sometimes enlarged at the 

 top, marked with thin parallel veins ascending from the base of the frond to 

 the top of the lobes without branching, being split in fascicles with the divi- 

 sions. To this section belong merely the genus Schizopteris, as characterized 

 by Prof. Brongniart for his Schizopteris anomala. 



It is difficult to separate these sections in genera by reliable and permanent 

 characters. Some othe species which are considered as Schizopteris by authors, 

 as Schizopteris adnascens, LI. and Hutt, for example, have the nervation and a 

 mode of division of their fronds similar to those of some Hymenophyllites, while 

 species referable to this last genus have, with a regular mode of division a nerva- 

 tion by disconnected fascicles of veins, like species of Aphlebia and Schizopteris. 

 This is the case with our Hymenophyllites splendens. The plants of the two 

 last divisions are little known, their apparently soft tissue having often been 

 destroyed by maceration. I have described and figured here some remarkable 

 forms, especially from the concretions of Mazon creek, whose study may throw 

 some light upon the nature and conformation of these singular vegetables. 



1. HYMENOPHYLLITES (proper). 

 HYMENOPHYLLITES ALATUS, Brgt. 



Veg. foss., p. 180, PL 48, fig, 4, 



This species is mentioned in the 111. Geol. Rep., vol. ii, p. 437, as present- 

 ing some characters at variance with the European one. Good specimens of 

 it from the concretions of Mazon creek, show it to be identical. 



HYMENOPHYLLITES TRIDACTYLITES, Brgt, 



Vg. fbss., p. 181, PL 5a 



Good specimens of tfais fine species have been lately procured from the roof 

 shales of the coal at Morris, by Mr. S. S. Strong, 



HYMENOPHYLLITES TRICHOMANOIDES, Brgt. 



Veg. foss, p. 182, PL 48, fig. 3. 

 A small specimen from the same place as the former. 



