494 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



delineated in a very misleading fashion by Schenk, thus giving a 

 truer glimpse of the unique vein system and showing more clearly the 

 filicoid aspect or the type, the fronds of which were regarded by the 

 distinguished French paleobotanist as probably pedalate, like those 

 of Clatkro'pteris. 



The specimens described by Schenk and Zeiller are all that have 

 been known of Gigantopteris until the discovery of numerous frag- 

 ments at a number of localities in the "red beds" Permian of the 

 Western Interior basin, i, e., in the Enid formation of Oklahoma^ 

 and the Wichita formation of Texas. 



In its nomenclatural history, as well as in other respects, the 

 genus under consideration is singular. Schenk, on learning, soon 

 after the publication of his memoir, that the generic name Mega- 

 lopteris had been preoccupied by Dawson ^ autographically substi- 

 tuted in pencil the name Idiophyllum, given by Lesquereux to a 

 specimen from the coal measures (Allegheny age) at Mazon Creek, 

 in Illinois. This name was inscribed by him in the text of the copy 

 presented by him to Zeiller and in the copy now in the library of the 

 United States Geological Survey. However, the original specimen 

 described by Lesquereux as Idiophyllum is included in the collection 

 presented by Mr. R. D. Lacoe, of Pittston, Pennsjdvania, to the 

 United States National Museum.^ On reviewing the material in 

 the Lacoe collection on the occasion of its transfer to the museum in 

 1893, the writer recognized in this type-specimen, which constitutes 

 one-half of a nodule, a somewhat macerated piima of Neuropteris. 

 Several years later the other half of the nodule, the counterpart of 

 the type-specimen, was found in the Geological Museum of Yale 

 University by Dr. E. H. Sellards, who identified it as Neuropteris 

 rarinervis,'^ thus disqualifying the name Idiophyllum from further 

 use in paleobotanical literature. Oigantopteris was a new name 

 penciled by Schenk, in substitution for Megalopteris, in the copy of 

 his paper now in the library of Dr. H. Potonie, in Berlm, as noted by 

 the latter in Engler and Prantl's Pflanzenfamilien,^ where Schenk's 

 manuscript name is for the first time put into prmt. Potonie places 

 the genus among the ferns without reference to any particular group. 



The American material embraces certain seeds and polleniferous 

 (sporif erous ?) scales so intimately associated with Oigantopteris and 

 partaking of so many of its characters as to seem to justify ])lacing 

 the genus provisionally among the Cycadofilices, or Pteridosperms, 

 rather than among the ferns. 



1 The plant-bearing horizons of the Enid formation (U. S. Oeol. Surv., W. S-. Paper 154, I'.iOG) probably 

 fall within the Chase stage of Kansas. 



2 Geol. Surv. Canada, Foss. Plant Dev. and Upper Sil. P'orm., Canada, 1871, p. 50. 



3 No. 1025S of the fossil-plant collection of the IT. S. National Musernn. 

 < Amer. Jour. Sci., scr. 4, vol. 14, 1902, p. 203. 



6 Engler and Prantl, Natiirl. Pflanzenfam., Leipzig, Teil I, Abth. 4, 1900, p. 513. 



