Bd. III: 14) THE MESOZOIC FLORA. I9 
which are simple, form a very acute angle to the midrib and are slightly bent to- 
wards it. 
The most characteristic features of this specimen are the remote position of the 
pinnæ and the shape and venation of the pinnules. The specimen might possibly 
represent a young frond, or the differently developed apical portion of one of the 
other species of CladopJilcbis; but is seems hardly possible that such a character as 
the peculiar venation could be explained in that way. Probably the specimen repre- 
sents a distinct type of frond different from the other species of Cladophlebis from 
the same locality, and, as it seems, from all others described as well. In regard to 
the venation, the closest analogy is found in some fronds described by Meer from 
Siberia under the name Dicksonia'^ (1876, pis. 17 — 18, different species) but in shape 
and mode of attachment of the pinnules none of his species bears any great resem- 
blance to the Antarctic specimen. 
Genus Coniopteris Brongniart. 
Coniopteris hymenophylloides (Brgn.). 
PI. 3, figs. 23, 24, 27 27 b ?, 28—30. 
Sphenopieris hvmenophvUi'ides, Brongniart 1828 æ, p. 51. 
Tympanopho 7 -a simplex, Lindley & HUTTON 1835, pi. 170 A. 
Tyynpanophora racemosa, Lindley & IIUTTON 1835, pi. 170 B. 
Coniopteris hymenophylloides, Sew.ard 1900, p. 99; pi. 16, figs. 4 — 6; pi. 17, figs. 3, 6 — 8; pi. 20, figs, i, 2; 
pi. 21, figs. I — 4. 
A number of specimens in the collection agree more or less closely with 
Sphenopteris hymenophylloides Brgn. P'ern-leaves of this type are subjected to a great 
variation as regards the degree of dissection of the lamina. It is often impossible 
to decide to what extent differences in this respect may represent specific distinc- 
tions or individual variation. This difficulty has resulted in a great confusion in the 
classification, which could be removed to some extent only through a comparative 
study of all the type-specimens of these ferns from different localities. Until this 
has been done, it appears best to fall back on the original diagnoses and type- 
specimens as much as possible. It has been shown, however, especially by Seward, 
that a great number of forms which differ somewhat from Brongniart’s type-speci- 
men of Sph. hymenophylloides must be included in that species. Seward’s classi- 
fication has been followed here on the whole. 
“ It has been proposed by Fontaine (in: Ward 1905, p. 72) that D. actitiloba Heer of the paper 
quoted should be referred, in the absence of fructification, to Cladophlebis. The same statement would 
evidently apply to some of the other sterile fronds figured by Heer under the name Dicksonia in the plates 
mentioned. It is doubtful, however, whether Cladophlebis is the right place for these forms. 
® Two figures have erroneously been numbered 27. The lower one will here be referred to as 27 a, 
the upper one as 27 b. 
