432 PALEONTOLOGY OF ILLINOIS. 



pinnately branching from a thin medial nerve, are thin, dis- 

 tant, oblique, arched, forking once only above the middle, each 

 branch ascending to the point of one of the teeth of the leaf. 

 This species has no relation with any other species of our Coal 

 Measures, except perhaps with Neuropteris fissa, Lsqx. (Geol. 

 Report of Pewn., p. 857), which it resembles only by the dis- 

 tant veinlets, and the large size of the leaves. 



Genus Odontopteris, Brgt. Frond bi or tripinnately branch- 

 ing ; pinnules variable, attached to the rachis by the entire, 

 sometimes decurrent or enlarged base ; medial nerve slightly 

 or not at all marked; nervules simple or furcate, some of them 

 emerging from the rachis and parallel to each other, some flabel- 

 late from the base and dichotomous. 



Odontopteris Wortheni, Sp. nov. PL 36, fig. 1 and 1 b. Frond 

 bipinnatiiid. Primary divisions alternate or opposite, ovate, 

 lanceolate, unequally lobed, either entire in the lower part or 

 scarcely divided, with a kidney-shaped leaflet under the point 

 of attachment to the main rachis, or pinnately alternately divi- 

 ded in obovate, obtuse, decurrent divisions, which are gener- 

 ally curved backwards and separated below the middle by 

 an acute sinus; terminal leaflet either cut in two obovate, obtuse 

 divisions, or entire larger, deltoid, obtuse, with short alternate 

 lobes near the base ; veins very thin and close, once or twice 

 forked, slightly arched, emerging from a large, flat medial nerve; 

 surface apparently covered with short, straight hairs. Though 

 this beautiful species has some of its large leaflets nearly entire, 

 with arched and dichotomous veins, like those of a Neuropteris, 

 it is evidently, by its parallel basilar nervation, a true Odon- 

 topteris. In the upper part of the frond the pinnse are deeply, 

 pinnately divided, while the inferior ones are more and more 

 entire, with always a kidney-shaped small leaflet attached to 

 the under side of this base. By these leaflets, and also by its 

 apparently hairy surface, this species has some likeness with 

 Neuropteris hirsuta; but it can not be considered as a variety of 



