DESCRIPTION OF THE SrECIES. 153 



immeaiately below it on the principal racliis ; ultimate pininc opposite, 

 terminated by a lobed tip, the pinnules ot" the lower portion havinji^ here 

 passed into more or less united lobes; pinnules small, opposite, thick, and 

 leathery, elongate elliptical, acute, narrowed gradually to the base and 

 inserted by a sort of petiole, decurrent to form a narrow wing; nerves 

 inconspicuous from inmiersion, brandling from a coumion point or a very 

 short nerve at the base of the petiole, diverging slightly, the secondary 

 branches forking once or twice. 



Locality : Red clay ball in banks of Dutch Gap Canal ; rare. 



This is a much smaller form than S. cllipfico, and more like S. Pomeli 

 Saporta, being, however, somewhat larger than that. 



SCLEROPTERIS DENTATA, Sp. nOV. 

 Plate LXIII, Fig.^. :i, 1. 



Frond bipinnate ? ; rachises slender, those of the ultimate pinna? 

 winged; pinnules with leathery leaf-substance, oblong to elliptical, acute, 

 greatly narrowed at base, and decurrent to form a wing; lower pin- 

 nules cut very obliquely into ovate-acute lobes, which pass in the pin- 

 nules higher on the frond and towards the tips of the ultimate pinna; into 

 triangular and shallow acute teeth; the ultimate pinna; (Fig. 3) terminate 

 with an oblong pinnule, which has at its summit three teeth ; nerves of 

 the pinnules composed of a slender midnerve, which sends off alternately 

 into each lol)e or tootli a deeply forked lateral nerve, sometimes having 

 one of the branches forking again. 



Locality : Fredericksburg ; quite rare. 



This fern shows a ci;rious blending of the features of Sclcroptcris and 

 Ctcnoptcris, standing midway between them. Perhaps it would be better 

 to make it a new genus. 



CTENOPTERIS, Brong. 



Frond bipinnate or tripinnate ; pinnae broadly linear-lanceolate, pin- 

 nate, and pinnatifid ; pinnules attached by the entire base, slightly decur- 

 rent, lower ones separate, upj)er ones slightly united at base, slightly curved 



