FOSSIL PLANTS. 433 



this polymorphous fossil fern, especially on account of the nerv- 

 ation. This nervation is apparently like that of Dyctiopteris 

 neuropteroides, Gutb., in Geinitz Verst., p. 23, tab. 28, fig. 6 ; 

 and if the short cross lines marked on the surface of the leaves, 

 and resembling short hairs, are divisions of the veinlets, our 

 species would be a new Dyctiopteris. But on account of the 

 fineness of the veins, it is impossible to decide if these lines — 

 generally placed in the same direction, but sometimes irregular 

 and even stronger than the veinlets, as marked in our fig. 1 b — 

 are true hairs or subdivisions of the veins, and thus constitute 

 a peculiar reticulation. Locality : Mazon creek, Grundy county. 



Odontopteris heterophylla, Sp. nov. PL 38, fig. 2-5. Frond 

 bipinnately and tripinnately irregularly divided ; pinnae lanceo- 

 late in outline or cordate ovate ; pinnules either entire, oblong 

 or obovate, obtuse, decurrent on the rachis, becoming broader, 

 shorter, cuneiform, even, kidney-shaped at the base of the 

 pinnae, or elongated, diversely lobed with unequal, long-linear 

 or short, lanceolate, pointed divisions ; terminal leaflet large, 

 ovate-deltoid, obtuse, with an obtuse alternate short lobe on each 

 side; veins sharply marked, inflated near the base, generally 

 twice, rarely thrice forking. In the decurrent leaflets the veins 

 are also somewhat decurrent on the rachis, as in fig. 2a; in the 

 oval, broad leaflets the veins are obliquely attached to it — fig. 

 4 a (somewhat enlarged, like the former) . This very variable 

 species is known only from small specimens, found only at 

 Murphysboro. The one of fig. 5 was presented to me by Mr. 

 James Sampson, of New Harmony, Indiana. The others were 

 found by Prof. A. H. Worthen and myself, and belong to the 

 State Cabinet of Illinois. 



Odontopteris subcuneata, Bunb. Quat. Geol. Journ., vol. 3, p. 

 23. It is somewhat doubtful if the branch of Odontopteris, 

 figured in our pi. 36, fig. 3, is the same species as that of M. 

 Bunbury. The general form of the leaflets, especially the 



55 Oot. 8, 1SC6. 



