518 Proceedings of the Royal Physical Society. 



in the British Museum all the lower pinnae are entirely 

 fertile. I am satisfied that the ovate-oblong sori are 

 generally single, and not clustered, and are two-lipped, the 

 slit passing one-third of the way down the sorus. The vein 

 is continued as a free receptacle in the centre of the cup or 

 cyst, as in existing Hymenophyllem, in which it is included, 

 not reaching beyond the entire portion. In some specimens 

 the receptacle is broad or thick, indicating the presence 

 of something besides itself in the cup, and giving the 

 appearance that would be produced if it v/ere covered with 

 sporangia ; I cannot, however, detect any indication on the 

 outer surface which might have been expected from the 

 individual sporangia. The compression of the specimens in 

 the rock, which has made the free receptacle appear like a 

 vein on the wall of the cup, together with the highly altered 

 condition of the rock in which the fossils are contained, 

 account for the imperfect preservation of the minute structures. 



"The interpretation which I have here given of the 

 fructification of this interestinof fossil exhibits so close 

 a resemblance to what we find in the living genus 

 Hymenophyllum that, were it not for the vegetative portions, 

 I would without hesitation place it in that genus." 



Crepin,^ in 1874, figured and described some specimens of 

 Archceopteris {Palmojpteris) hihernica, var. minor, from fivieux, 

 Belgium, of which he also figures the fruit, but does not 

 describe it in detail. 



As the generic name Palcf^opteris, adopted by Schimper for 

 this and some allied ferns, had been previously employed by 

 Geinitz ^ for a fossil which he supposed to be a fern-stem 

 (but which has been discovered to be the stem of Cordaites), 

 Dawson,^ in 1882, proposed the name Archceopteris for the 

 plants placed in Palmopteris, Schimper (not Geinitz). 

 Dawson's genus Archa^opteris must therefore be employed for 



^ "Description de qiielqnes plantes fossiles de I'etage des psammites du 

 Condroz (Devouien siiperieur)," Bull. Acad. roy. d. Belgique, 2^ ser., vol. 

 xxxviii., No. 8, Aug. 1874. 



" Vers. d. Steinkf. in Sachsen, p. 32; see also Grand'Eury, Flore carbon, 

 du Depart, de la Loire, pp. 241 and 243. 



2 Foss. Plants of the Brian (Devonian) and Upper Silurian Formations of 

 Canada, part ii., p. 98 (1882). 



