RUFFORDIA. 79 
The small piece figured by Trautschold as Sphenopteris Auerbacht, 
Traut., from the Klin Sandstone seems to be identical with some 
forms of Ruffordia Gopperti, as first suggested by Schenk.’ Schenk 
compares Ruffordia Gépperti with Sphenopteris Stenstrupi, Hr., and 
S. Hinslopi, Old.; his figures represent imperfect pieces of pinne. 
There is no mention of this species by Fontaine in his ‘‘ Potomac 
Flora;” one of his species, S. acrodentata,? founded on a very 
small fragment, seems to be almost identical with the broadest 
forms of our English species, and especially with such as I propose 
to consider as Ruffordia Gépperti, var. latifolia. From the small 
piece figured by Fontaine it is impossible to form any idea of the 
habit of the fern; the character of the pinna represented by him 
in fig. 4, pl. xxxiv. seems to be very much the same as that of 
Thyrsopteris brevipennis, Font., represented in the same plate, 
figs. 3 and 3a; in the former the pinnules are dentate, in the 
latter entire. 
In addition to the specimens figured by Nathorst from Japan 
as S. Gépperti, those fragments described and figured by Yoko- 
yama as Thyrsopteris Kagensis, Yok.,° should be compared with the 
present species; there is no adequate reason for referring them to 
the genus Zhyrsopteris. 
Repeated examinations and comparisons of a large number of 
specimens in the Museum Collection, have led me to regard Ruffordia 
Goépperti as a species of which the vegetative parts are extremely 
variable, and to a much greater extent than the figures hitherto 
published would lead us to expect. The task of determining, or 
attempting to determine, what limits to assign to this species has 
been attended with considerable difficulty, and the conclusion 
arrived at is one which will doubtless suggest that two or more 
specifically distinct forms have been included under one name. 
My first inspection of the material favoured the view of two or 
three species or, at any rate, varieties; but a more detailed 
examination forced me to the conclusion that I was dealing with 
a number of specimens, which could be arranged in a regular and 
gradually varying series, with a marked difference in form 
between the extreme types. 
1 Paleontographica, vol, xix. p. 261. 
? Potomac Flora, p. 90, pl. xxxiv. fig. 4. 
§ Journ. Coll, Sci. Japan, vol, iii, 1890, p. 23, pl. i. figs. 6 and 6a, 
