FEENS— MEGALOPTERIDE.E— ODONTOPTERIS. 1 25 



referable to the Neurodontopteris of Potoni^, which, as Sterzel remarks/ is 

 largely identical with the Mixoneura of Weiss. Without discussing the 

 relations of these two genera, it may be remarked that the genus CaUipte- 

 ridium as now employed seems to include two quite different groups. 

 C. SuUivanfii (Lx.) Weiss l^elongs to the Neurodontopteroid group, and is 

 probably entirely distinct from the later, Pecopteroid, group, some of the 

 representatives of which, including several fertile forms, are, in my opinion, 

 o-eneticallv bound to the closely resemblant forms of Pecopteris. 



I have not seen an}^ rachial pinnules intermediate to the pinnae, such 

 as are characteristic of the genus according to Zeiller's definition, although 

 several fragments are present in which the pinnge are still alternately con- 

 nected with the broad striated rachis. 



The nervation and common form of the pinnules, which frequently 

 overlap, are finely illustrated in Figs. 1. 2, PI. XXXIX, and in Weiss's 

 "Studien iiber Odontopteris."" 



Localities.— Owen's coal bank, U. S. Nat. Mus., 3587, 3589; Pitcher's 

 coal bank, U. S. Nat. Mus., 3588, 5660, 5674; Gilkerson's Ford, U. S. Nat. 



Mus., 3598. 



ODONTOPTEEIS Brongniart, 1822. 



1822. Filicites sect. Odontopteris Brouguiart, Mem. mus. bist. uat., vol. viii, p. 234. 



1826. Odontopteris Sternberg, Versuch, vol. i, tent., p. xxi. 



1828. Odontopteris Brouguiart, Prodrome, p. 60. 



1870. Odontopteris Weiss, Zeitschr. deutsch. geol. Gesell., vol. xxii, p. 859 (pars-). 



1870. Mixoneura Weiss, Zeitschr. d. deutsch. geol. Gesell., vol. xxii, p. 864. 



1870. Xenopteris Weiss, Zeitcher. d. deutsch. geol. Gessell., vol. xxii, p. 865. 



Odontopteris! Bradleyi Ls. 



PL XLII, Fig. 2. 



1870. An Odontopteris Bradleyi Les(iuereux, Rejit. Geol. Surv. Illinois, vol. iv, p. 390, 



pi. viii, fig. 1"? 

 1880. Odontopteris Brardleyi Lesijuereux, Coal Flora, vol. i, p. 140. 



The specimen illustrated in Fig. 2, PI. XLII, is an interesting example 

 of the heteromorphous Neuropteroid or Odontopteroicl fragments at present 

 included among the American species of Odontopteris. As seen in the 

 fio-ure, we have a broad, somewhat lax, striated axis, on the left of which is a 



1 Fl. Rotlil. Oppeuau; Mitth. Grossherzl. Badenscheu Geol. Landesaust., vol. lii, 2, 1895, p. 283. 

 ■=Zeitschr. d. deutsch. geol. Gesell., vol. xxii. 1870, p. 876, pi. xxi, ligs. 1-3. 



