FERNS^PEGOPTERIDE-E— PECOPTERIS. 79 



nervils seem to be always simple, and the racliis is punctate. In fact, I 

 should have but little hesitation in referring the fragments to the former 

 species were it not for a slight decurrence of the midrib and the distinctly 

 villous upper surface of the fertile pinnules. So well marked, however, 

 are these characters that a definite reference of our specimens to that 

 species is plainly not allowal^le. Still, not wishing on the evidence of the 

 material before me to add to the nomenclature of this already highly 

 differentiated group, I leave the fragments from Missouri, one of which 

 is seen in PI. XXXVI, Fig. 3, with a reference that is both tentative and 

 comparative. 



Considerable difference as to the punctatiou of the rachises exists 

 between the specimens from different regions or horizons described by dif- 

 ferent authors as Pecopteris arborescens. In the speciixiens from Missouri a 

 rachis less than 4 mm. in length is provided with rather distant, very open, 

 upward-curving spines, round at the base, and nearly 2 mm. in length. 



To the form described above probably belongs a specimen from the 

 same region ^ labeled b}^ Professor Lesquereux as Pecopteris cequalis Brongn. 

 The pinnules in this specimen, PI. XLIV, Fig. 3, 3'', are, however, more 

 than twice as long as, and broader at the top than, those of one of Brong- 

 niart's types- which, in verification of Brongniart's intimation, has been 

 referred by Schimper and Zeiller to P. pennaiformis. 



Locality.— Gilkerson's Ford, U. S. Nat. Mus., 5588, 5595, 5596. 



A doubtful fragment which, the nervation being obscure, may belong 

 to P. vestita Lx., is from Pitcher's coal bank, U. S. Nat. Mus. 5686. 



Pecopteris (Astbrotheca) hemitelioides Brougu."? 

 PL XXXV, Fig. 5. 



Among the hundi-eds of fragments of Pecopteris from Hobbs's bank is 

 a single specimen, which, though failing to show certain important diagnos- 

 tic characters with sufficient clearness to make positive its identification as 

 Pecopteris hemitelioides Brongn., seems nevertheless to coincide so far with 

 that species in its visible features as to justify its provisional designation by 

 the same name. This fragment, some idea of the outlines of whose pinnse 



' No. 4873 of the Lacoe ccillection, U. S. Nat. Mus. 

 ''Hist. veg. foss., p. 34.3, pi. csviii, figs. 1, 2. 



