FERNS— MEGALOPTEEIDEJ3—NBUEOPTEEIS. 131 



Fronds bi- or tripinnate, dense, the divisions alternate, open at a riglit 

 angle, or nearly so, to the rachis, the rachis being broad and striate; pinnte 

 nsually close, contiguous, or overlapping, sometimes slightly narrowed at 

 the base, the sides parallel in the middle, often somewhat rounded at tlie 

 tip; pinnules alternate, rather thin, open, the lateral ones ovate when small, 

 becoming oval and oblong, rounded at the top, close, usually slightly imbri- 

 cated, nearly bilaterally symmetrical, slightly subfalcate, entire to the sub- 

 terminal lobe, sessile by the base of the broad midrib, the sides nearly 

 equally rounded at the base; terminal pinnule large, very long in the 

 young pinnae, oblong-deltoid, oblong-ovate, or rarely deltoid-ovate, obtusely 

 rounded at the apex, with not more than one connate basal lobe; midrib 

 distinct, broad, striate in the large pinnules, dissolving above the middle; 

 nerves distinct near the midrib, sometimes immersed in the lamina, origi- 

 nating at a narrow angle, forking at or near the base, often with three sub- 

 sequent dichotomies at a narrow angle while arching gradually to meet the 

 margin nearly at a right angle, where they number 34 to 40 per centimeter. 



This species, which is very nearly related to Neuropteris ftexuosa Stb. 

 and N. vermicularis Lx., is distinguished chiefly by its open pinnse, the 

 oblong or oval rather thick pinnules, slightly imbricated, sessile, and nearly 

 equally rounded at the base, with the midrib distinct, the lateral nerves 

 distant and large near the midrib, forking several times in passing to the 

 border, which they meet obliquely. The illustration given in the Coal 

 Flora,^ as well as our Fig. 4, PL XLII, well expresses the characteristic 

 form of the smaller pinnae and of the pinnules. The terminal pinnules of 

 the longer pinnae are, however, not always so oblong and obtusely rounded, 

 as is shown in Fig. 3, PI. XLV. The appearance of the larger pinnules is 

 illustrated in the same figure, or in Fig-. 4, PI. XLI. The specimens in 

 hand agree well with the type, kindly loaned for comparison by Dr. J. H. 

 Britts, as well as with other examples determined by Professor Lesquereux 

 and now included in the Lacoe collection. The fact that Neuropteris mis- 

 souriensis so much resembles N. flexuosa perhaps accounts for the inclusion 

 of the latter species in the list of the fossils of Missouri published by Mr. 

 Hambach.^ I have not seen any representative of the latter species from 

 Henry County, the locality given by that author. 



>P1. vii, fig. 5. 



2 Hambach, Bull. Geol. Surv. Missouri, No. 1, 1890, pp. 60-85. 



