92 CLADOPHLEBIS. 
venis creberrimis tenuissimis obliquis furcatis; rhachi gracili 
tereti.” 
The much more perfect material at present available necessitates 
an extension and modification of the original diagnosis. 
Frond bipinnate, rachis flat and broad, pinne linear lanceolate, 
alternate to opposite, pinnules falcate, contiguous, attached by the 
whole of the broad base, acuminate, margin entire or slightly 
dentate towards the apex. 
Brongniart, in his ‘‘ Tableau,” includes Meuropteris Albertsii, 
Dunk., among the Wealden plants under the name Cladophlebis 
Albertsti. Ettingshausen recognized a certain resemblance in 
Dunker’s species to Alethopteris, and adopted that generic name. 
This change is accepted by Schimper, who remarks on the 
difficulty of determining the true position of the species from 
the fragment figured by Dunker. 
In 1871. Schenk! notes the close resemblance of Alethopteris 
Albertsti, Schimp., to A. Résserti, Schenk, A. insignis, Lindl., and 
A. Whitbyensis (Brong.); he figures part of a pinna, which, in 
spite of certain minor differences, is referred to Dunker’s species. 
The same author? draws attention to the resemblance between 
Pecopteris Whitbyensis, Brong., as figured by Zrautschold,? and 
Alethopteris Albertsit (Dunk.). 
Heer includes several Greenland specimens from the Atane beds 
under Pteris (?) Albertsit (Dunk.), but they do not all appear to 
be quite the same as Cladophlebis Albertsit; some of the figures, 
however, show a close resemblance to this species. The same 
genus is adopted by Velenovsky for a fern figured by him as Péeris 
Albertini (Dunk.), from the Bohemian Cretaceous beds. He draws 
attention to the complete correspondence between the Bohemian 
species and the specimens described by Heer from Greenland, but is 
not decided as to the relationship between Heer’s species and the 
original Wealden species of Dunker. Some of Velenovsky’s 
figures bear a strong resemblance to the English specimens, and 
might perhaps be included in the synonomy of the species ; this is the 
case with his fig. 10, also figs. 6, 7, and 8; but figs. 5 and 9 seem to 
me rather more like the specimens referred by this author to Pteris 
1 Paleeontographica, vol. xix. p. 218. 
2 Ibid. p. 261. 
8 Nouv. Mém. Soc. Nat. Moscou, vol. xiii. 1870, pl. xix. fig. 2. 
