A. OC. Seward—Cyclopteris from the Coal-mcasures. 345 
species of Cyclopteris, none of which exactly correspond to my 
specimen, Cyclopteris obliqua, which is represented as an isolated 
petiole, being the most like it. In his later work’ Brongniart 
divides the Cyclopteroid forms into two genera, Cyelopteris and 
Nephropteris: the former he defines as follows :—‘ Fronde simple, 
pédicellée, symétrique, arrondie, cordiforme, ou flabellée, entiére ou 
lobée, sans apparence de nervure médiane, toutes les nervures 
partant de la base du limbe, et se divisant en se dichotomant pour 
atteindre la circonférence.” 
Cyclopteris reniformis, C. trichomanoides, C. digitata, etc., belong 
to this genus. 
The genus Nephropteris which is thus defined :—‘“ Frondes isolées, 
simples, sessiles, obliques, non symétriques, arrondies ou cordiformes, 
ordinairement concaves et ombiliquées & leur base ”—includes such 
forms as Cyclopteris obliqua, C. oblata, C. orbicularis, etc. These 
species are regarded by Brongniart as a distinct group ; he considers 
them to be anomalous basal leaves, referable probably to the genera 
Neuropteris and Odontopteris. 
Lindley and Hutton? give two figures of Cyclopteris obliqua; they 
point out that the absence of any stalk and the trace of what seems 
to them a distinct disarticulation favour the idea that the specimens 
originally formed parts of compound leaves. This being the case, 
they consider them referable to Neuropteris rather than Cyclopteris. 
It is also suggested by these authors® that Neuropteris ingens may 
have belonged to the same plant as Cyclopteris obliqua. 
In the “Illustrations of Fossil Plants,” edited by Prof. Lebour,* 
there is a figure of Cyclopteris (Nephropteris) obliqua which shows 
two pinnules attached toa rachis; this specimen closely resembles 
the one I have figured, except in its much smaller size. 
In his earlier writings Lesquereux® retains the genus Cyclopteris, 
and considers that all Cyclopteroid leaves attached to stems form a 
distinct genus: those without stems and with arched nervures are 
included in Neuropteris, those without stems and with straight and 
diverging nervures are classed with Odontopteris. The Cyclopteroid 
leaves with stems are retained in the genus Cyclopteris, which is sub- 
divided into three sections :—(a) Adianthoides. (8) Odontopteroides. 
(1) Neuropteroides. 
In the description of fossil plants in the Report of the Geological 
Survey of Illinois, Lesquereux® no longer regards Cyclopteris as a 
distinct genus, further evidence having been obtained in favour of 
the connection of Neuropteris and Cyclopteris. Neuropterts is defined 
so as include leaflets without a median nervure. 
1 Tableau des genres de végét. foss., considérés sous le point de vue de leur classi- 
fication botanique et de leur distribution gélogique, p. 16 (1849). 
2 Fossil Flora, pl. 90 (1831-1837). 
3 Fossil Flora, vol. ii. p. 28. 
4 Tllust. of Fossil Plants, p. 23, pl. 11. 
‘ Cae of Fossil Plants in Geology of Pennsylvania, by H. D. Rogers, vol. 
ll. 8). 
a Oa oe of Fossil Plants in Report Geol. Survey of Illinois, yol. ii. p. 427 
