FERNS— SPHENOPTEKIDE.E—ALOIOPTElilS. 71 



The specimen shown in PL XXIII, Fig. 6, is of the same character 

 as the large fragment figured by Professor Lesquereux. Some of the slen- 

 der pinnae of this type attain a length of 6 cm. or more. The pinnules 

 in the middle of the pinna often show two well-developed shai-p teeth, 

 though the latter are not so cristate as in the preceding species. The 

 small fragment of a young compound pinna seen in PI. XXIII, Fig. 1, 

 strongly resembles this species; but by its nervation and the develop- 

 ment of the pinnules it belongs more properl)^ to A. Winslovii, next to 

 be described. 



The rock fragment, from the vicinity of Clinton, photographed in 

 PI. XXIV, Fig. 3, shows two segments (No. 2386 of the Lacoe collection) 

 identified by Professor Lesquereux as Pecopteris erosa, the larger of which 

 approaches A. Winslovii, while the other preserves the apex of a compound 

 pinna. But although the lateral pinnae on the larger segment are nearly 

 of the size frequently found in the A. Winslovii with which it has been 

 thought it might perhaps belong as a younger stage, they show fairly well 

 the difference in the pinnules and the margins. 



In the American specimens of Aloio-pteris erosa the pinnules are broader 

 in proportion to the size of the pinna, and not so constricted; the ujDper 

 border is much more nearly truncate, the sinuses not so deep proportionately, 

 while the nerves, which are not so distinct in the rather thicker lamina, fork 

 near the base at a narrower angle, and arch, especiall}^ the upper branch, 

 rather strongly upward in passing to the margin, approaching in this respect 

 the P. serrula Lx. When the pinnule has three teeth the upper ner\'il forks 

 again at a rather narrower angle than in A. Winslovii. 



I have not observed any fertile pinna that seems referable to this species 

 among the material from Missom-i. One fertile specimen from Morris, 

 Illinois, identified under this name by Professor Lesquereux, has the same 

 general aspect as the fertile pinnae of A. Winslovii, though the pinnae are 

 narrower and the marginal filaments do not appear. It would seem, as in 

 the latter species, to represent more probably Corynepteris, to which genus 

 it has been referred by Kidston.-" 



Localities. — Pitcher's coal bank, U. S. Nat. Mus., 5562, 5563, 5614, 5721 ; 

 ailkerson's Ford, U. S. Nat. Mus. 5561. 



' Trans. Roy. Soc. Edinb., vol. xsxiii, 1887, p. 381. 



