FERNS— MEGALOPTERIDI'LE—NE UROPTEIIIS. 127 



is quite possible that tlie fragment should l)e placed in Odontopteris 

 subcuneata Bunb. Specimen No. r25(> comes from St. Clairsville, Ohio, 

 and is probabh* one of those mentioned in the description given in Coal 

 Flora, vol. i, p. 140. 



It is interesting to note in this connection that nearly all of the above- 

 named species are more or less distinctly hirsute, as is the condition of the 

 specimen from Missouri, though the fine, short, bristle-like hairs are deli- 

 cate and quite obscure, compressed upon the fleshy lamina- of the pinnules. 

 The strongly Neuropteroid characters present in some of the specimens 

 placed by Lesquereux in Odontopteris Wortheni, 0. subcuneata, and 0. affinis, 

 tog'ether with the fact that these species have, so far as I can learn, very 

 rarely been reported from beds in which one of the long-pinnuled species 

 of Neuropteris, such as N. Sclieuchzeri Hoffm., N. deciinens Lx., or N. hirsuta 

 Lx., was not also present, afford a basis for the suspicion that these partic- 

 ular specimens, if not the entire species to which they are referred, should 

 be regarded as anomalous or heteromorphous pinnje and pinnules of the 

 genus Neuropteris. This suspicion is fostered by the great difficulty in 

 some instances encountered in deciding as to which of the two genera cer- 

 tain specimens should be referred. For example, the fact that the pinnules 

 of these species of Odontopteris from Mazon Creek, Illinois, have a coarser, 

 more distant nervation than those from other regions placed in the same 

 species, just as Neuropteris decipiens or N. fascictdata from Mazon Creek 

 differs from the forms of N. SchetKhzeri hi other localities, seems to indicate 

 a certain coordination or agreement in nervation between the species from 

 the same localit)' placed in both genera. In many cases it would seem that 

 neither the nervation of the large basal segments or lobes, when the latter 

 are present, nor the presence of hairs affords a satisfactory criterion for a 

 generic distinction of the forms. 



Locality. — Owen's coal bank, U. S. Nat. Mus., 5623. 



NECTEOPTERIS Brougniartj lS2li. 

 Classification veg. foss., p. 33. 



The definite systematic relationship of the Neuropterid group is still 

 not wholly established. Although within the last few years a number of 

 new species have been discovei'ed, and some interesting studies of the 

 structure of the petioles in certain members of the famih- have been made, 



