DESCRIPTION OF SPECIES. PP. 113 



species S. oxydata, and is its representative in our flora. 

 It is also allied to the S. lyratifolia of Heer. 



Grand' Eury is disposed to regard the Sphenopterids of 

 this type as forms of Callipteris. This view is conlirmed 

 by the leather-like character of S. coriacea, and by the fact 

 that it occurs associated with Callipteris conferta. At any 

 rate the type of Sphenopteris shown in S. coriacea, is ex- 

 clusively Permian. 



The genus Cymoglossa, founded by Schimperon one spe- 

 cies, is exclusively Permian. Its very considerable devel- 

 opment in our flora is of great weight as indicating a period 

 later than the true Coal Measures. The plants of this 

 genus are evidently modifications of the Goniopteris type, 

 which is itself characteristic of the closing period of the 

 Coal Measures and of the Permian. 



The genus of Nematophyllum, in the absence of mid-nerve 

 in the leaflets, in their great elongation without marked 

 change of width, and in their union, at least at base, is allied 

 to the genus Schizoneura, which begins in, and is highly 

 characteristic of the Permian. 



We may state here that we hesitated for sometime about 

 separating this plant from Schizoneura, and were finally in- 

 duced to do so from the fact that we nowhere saw the leaf- 

 lets united together, and attached unmistakably to a stem. 

 The union of the leaflets in the young state is the most im- 

 portant character of the genus Schizoneura. Yet we saw 

 many fragments of leaves, having precisely the texture, 

 striation, &c. of the leaflets of Nematophyllum, which 

 were an inch or more wide, and showed a sj)litting, to a 

 greater or less depth, into thread-like lacinise of the width 

 of the leaflets of Nematophyllum. These were never 

 attached, and if they represent the united younger leaves 

 of a Scliizoneura they must be very deciduous. 



The authors of the European species of Schizoneura, 

 however, seem to attach little value to this union in the 

 younger leaves. Schizoneura Meriani, Schimp. of the 

 European Trias, closely resembles our NematophyHum in 

 many other features, as vi^ell as in the separation of the 

 leaves. Heer in his "Pfl. der. Trias u. Jura," states 

 8 PP. 



