388 
PALEONTOLOGY OF ILLINOIS. 
b2i /• (j. 
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of this kind on the veinlets of Neuropteris cordata , Brgt., and which is also 
often remarked on specimens of our A T . hirsuta, has been considered by Euro¬ 
pean authors as representing organs of fructification. As the form and thick¬ 
ness of the inflation is very irregular, it may be caused on both species by some 
casual influence in the process of mineralization. The basilar leaflets of this 
species show a tendency to be divided into lobes and pinnules, having thus the 
same form as some of those of Neuropteris Desorii, Lesqx., to which this spe¬ 
cies is related, and from which it differs only by the thick epidermis, and by 
the more distant ramification of the veinlets. The small fragment mentioned 
in vol. ii of this Report, p. 430, as possibly belonging to N. Desorii, Lesqx., 
is referable to this species. 
Genus DICTYOPTERIS, Gutbier. 
Aldr. u Verst., p. 62. 
Frond at least tripinnate, pinnse linear-lanceolate, bearing 
alternate leaflets much variable in size, ovate-oblong obtuse 
squarely cut at the base, with equal lobes on both sides, or 
with the lower lobes slightly elongated. Medial nerve none, 
or merely basilar; veinlets anastomosing from the base, arched 
towards the borders, but irregularly undulating in ascending, 
and forming by their contact an oval-polygonal reticulation. 
leaflet, somewhat broader and longer, is oval in outline, ob¬ 
tuse, and cut on one side into a short obtuse lobe, fig. 2. The 
leaflets of the large inferior pinnse are more distant, larger, 
truncate at the base, slightly scythe-shaped outwards; and 
