L, Lesquereux on the Coal Formations of North America. 207 
resemble the genus Pveris constitute a separate i Gene- 
rally larger than the other species of the tribe, their fronds are 
-pinnately or even pinnately parted. The strong medial nerve 
of the leat P +? 
above definition and not extended beyond its limits, as has 
been done by Unger. The known American species belong- 
: both continents. As exclusively American species we have: 
teris P, 
a ly referred to A. urophilla Brgt., (Penn. Geol. Rep., p. 864) 
: Vol. iv, ined :) and A. disians Lsqx., if this species founded 
on two small and imperfect specimens proves to be a one. 
Ou Coxiana Lsqx., innit resembles A. sinuata Brgt, Its 
*condary veins are more oblique than those of any other species 
of the genus. It is thus intermediate between this and the fol- 
ae division. d by B jart for another 
© genus Callipteris,* pro rongni 
GAD of foenil ers ce veldeed vo the dee b 
~ oy anc 
Tachis by their whole base and generally united together. Prof. 
Séppert formerly referred the species of this group to a peculiar 
“ection of Neuropteris, and I admitted the same views In the 
* ms . 
This Callipteri i Mr. John Smith to a genus of living ferns 
oben ateat strain 
