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 O. elongata, figured by 
Geyler, to those of O. Mantelli (V. 1069, Pl. III. Fig. 4) has 
already been referred to, 
In Richthofen’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, O. elongata 
(Geyl.). 
Schenk’s figure of Sphenopteris Gopperti, referred to in the 
synonomy, seems to me indistinguishable from O. elongata. Cf. 
Schenk, Paleeontographica, vol. xix. pl. xxx. fig. 2, and Pl. II. 
Fig. 2 of this Catalogue. 
Yokoyama, in the first of the two papers referred to above, 
includes O. 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 Dieksonia. He 
speaks of the species as the ‘‘ chief and characteristic fossil of the 
Japanese Flora, being found in all of the fossil localities.” From 
Fontaine’s long list of the species of Zhyrsopteris I have included 
one as a synonym of O. 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 :? 
‘Tt 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. JDantelli, Brong.; 
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. Gépperti.” 
Here we have forty new species founded on sterile fronds, or 
1 Loe. cit. p. 28. 
2 p. 120. 
