124 I). WHITE — A NEW TjENIOPTEROID FERN AND ITS ALLIES. 



Neuropteris, 1 becomes, in the Lower Carboniferous, alethopterokl in its 

 mode of development and configuration, while its nervation is that of 

 Alethopteris or Odontopteris. The pinnules are further distinguished by 

 their thick midrib, which is canaliculate above, semi-cylindrical beneath, 

 nan-owing in passing up, but distinct to the apex of the lamina. Les- 

 quereux, who frequently pointed out its ancestry to, or at least its com- 

 mon descent with, the neuropterids, adds 2 that " except for the characters 

 of the nervation [open, curving, close, dichotomous] this genus is not 

 separable from Danseopsis, I leer. Saporta and Marion :i include the genus 

 Megalopteris with Cannophyllites, Brgt., in the Cannophyllitess, which they 

 regard as being near the Dolerophylhas among their " Progymnosperms," 

 a- view in which Count Solms-Laubach and Schenk do not concur. 

 Between the more alethopteroid forms of Megalopteris, such as M. hartii* 

 M. ovata, 5 M. minima, 6 M. abbreviata 1 and the alethopteroid genera found 

 in the Lower Carboniferous of Ohio and West Virginia, the resemblance 

 is so close as at once to force a comparison. 



Among the forms from below the Maxville limestone in Ohio, the 

 generic delimitations of which are perhaps more artificial than is com- 

 mon even among Paleozoic ferns, the Alethopteris maxima, And., 8 is found 

 to have a close tamiopteroid nervation in pinnules which are decurrent 

 and confluent in the upper part of the pinna, but scarcely confluent in 

 the lower part, where their mode of clecurrence, in a semi-auricle, is nearly 

 that given as a chief characteristic of Orthogoniopteris, regarded by An- 

 drews, its author, as comparable to Angiopteridium and Neriopteris, with 

 many of the characters of Dansea. 9 Alethopteris holdeni of Andrews 10 is 

 described by Lesquereux " as agreeing in most respects with Orthogoniop- 

 teris, but is removed by him to form a new genus, Protoblechnwm, its nerves 

 being rather more curved than in Orthogoniopteris, while it is excluded 

 from Alethopteris by its supposed simply pinnate fronds. It would, per- 

 haps, be not incorrect to designate these " Waverly " forms, occurring in 

 the same deposit with the above-mentioned species of Megalopteris, as 

 Alethopteroid megalopterids. Neriopteris, from the conglomerate series of 

 northern Ohio, with its sessile or short-petioled pinnules and oblique 

 nervation, in fineness and regularity rivaling that of Macrotaeniopteris, has. 



1. Foss. PI. Dev. Upp. Sil. Can., p. 51, p!. xvii, tigs. 191-194. 



2. Coal Flora, I, p. 148. See Ann. Rep't Geol. Surv. Pa., L886, pt. 1, p. 47.".. 



3. Evol. re,g. veg., Phanerog., p. 77. 



4. Andrew s, < Jeol. Surv. < >hio.. Pal. II, p. 416, pi. xlvi, figs. 1, la. 



5. Ibid., p. 417, pi. xlvii. figs. 1, '-', 2a. 



6. Ibid., p. 4lii, pi. xlviii, figs. l-:s. 



7. Lesquereux, Coal Flora, p. 151, pi. xxiv, fig. :;. 



8. [bid., p. 421, pi. 1, figs. 3. ■;n-h. 



9. [bid., |>. tl.s. pi. 1, figs. 1, la. 



10. Ibid., p. 420, 1)1. li, figs. 1. 2, 2a, 



11. Coal Flora, v.,i. I. p. L88, 



