56 ONYCHIOPSIS. 



Siberia and Amurland, and considers the resemblance close enough 

 to justify the inclusion of the Japanese species in the same genus. 

 The resemblance between the fertile axis of 0. elongata, figured by 

 Geyler, to those of 0. Mantelli (V. 1069, PI. III. Fig. 4) has 

 already been referred to. 



In Bichthofen's "China" Schenk figures some portions of a 

 frond from Japan, without any more exact locality, which he 

 places with Geyler' s species. Most probably, as Schenk points out, 

 this specimen belongs to the common Japanese type, 0. elongata 

 (Geyl.). 



Schenk's figure of Sphenopteris Gopperti, referred to in the 

 synonomy, seems to me indistinguishable from 0. elongata. Cf. 

 Schenk, Palaeontographica, vol. xix. pi. xxx. fig. 2, and PI. II. 

 Fig. 2 of this Catalogue. 



Yokoyama, in the first of the two papers referred to above, 

 includes 0. elongata in his list of fossils under the name Dicksonia 

 elongata ; in his second and more important work, the genus 

 Onychiopsis is substituted for the original name of Diclcsonia. He 

 speaks of the species as the " chief and characteristic fossil of the 

 Japanese Flora, being found in all of the fossil localities." x From 

 Fontaine's long list of the species of Thyrsopteru I have included 

 one as a synonym of 0. elongata; but it is not at all unlikely that 

 several of the Potomac " species" ought to be placed, if not in the 

 same species, at least very near to the Japanese form. In the 

 general remarks at the end of the Potomac Monograph we have 

 the following statement with regard to the genus Thyrsopteris : 2 

 1 ' It is true that, as no fructification has been found on these ferns, 

 they may be incorrectly placed in the genus Thyrsopteris" " The 

 species," says Fontaine, "most of them well characterized, number 

 forty." A number of them are described as possessing "the same 

 type of foliage as the Wealden ferns, S. Mantelli, Erong. ; 

 S. Gopperti, Dunker; S. Cordai, Schenk; S. plurinervia, Heer; 

 and S. Gomesiana, Heer." Lastly, we are told, "most of them 

 are new and unique. One or two have some resemblance to 

 Oolitic species, while a greater number may be grouped as belong- 

 ing to the two Wealden types, S. Mantelli and S. Gopperti." 



Here we have forty new species founded on sterile fronds, or 



1 Loc. dt. p. 28. 



2 p. 120. 



