410 PALAEONTOLOGY OF ILLINOIS. 



be some error of description or of illustration of the European species, which 

 is marked as having its surface entirely smooth, while the figure shows it cov- 

 ered with points or rugose. 



Abundant in the shales of the coal at Morris. 



SPHENOPTERIS TRIFOLIATA, Brgt. Veg. Foss., p. 202. 



PI. 63, fig. 3. 

 In the shales of Colchester ; found by Prof. A. H. Worthen. 



SPHENOPTERIS ELEGANS, Brgt. Veg. Foss., p. 172. 



PL 53, fig. 1 and 2. 



Two fine specimens of this species have been obtained from the concretions 

 of Mazon creek; by Mr. M. S. Hall. 



GENUS HYMENOPHYLLITES, Gopp and auct. 111. Geol. 

 Rep., vol. ii, p. 436. 



In preserving this genus, with its characters too vaguely defined as it is in 

 vol. 2 of this Report, p. 436, it would be advisable to subdivide it as follows : 



1. BymenaphylKtes proper, containing species with a generally inenibra- 

 naceous delicate frond, pinnately divided, the primary divisions alternate or 

 dichotomous, decurrent on the rachis and ultimate lobes linear obtuse, either 

 simple alternate or irregularly divided ; nerves percurrent pinnately branching, 

 ascending, simple in each lobe. This section contains Hymenophyllites and 

 Trichomanites, Gopp. 



2. Aphlebia, including species with fronds of various sizes and forms, gen- 

 erally with a broad rachis and more or less irregularly divided, the divisions 

 rather dichotomous or pinnatifid, entire or variously laciniate lobed, the lobes 

 sometimes enlarged and recurved ; veins parallel and numerous from the base 

 of the fronds, dividing in fascicles from the rachis in each primary division, 

 and passing by subdividing, as simple veinlets to the point of each lobe. To 

 this section are referable the genera Aphlebia, Schizopteris, Rhodea, Pacliy- 

 phyllum, etc. auct.* 



*W. P. Shimpcr, in Pal. Veg., makes for this section a new genus, Rhacophyllum. 



