44 ONYCHIOPSIS. 
‘Geology of Sussex,’ refers to the method of branching in S. 
Sillimani as unlike that of ferns, but suggests it may possibly be 
the skeleton of part of a frond. It is true that Mantell’s specimen 
does not by any means closely resemble a typical Onychiopsis 
Mantelli fragment, but it agrees fairly well with some of the 
more fragmentary and less defined specimens. Schenk? decides 
to regard Confervites fissus, Dunker, as a fragment of O. Mantelli, 
and is led to this conclusion from an examination of Dunker’s type 
specimen. There is no appreciable difference between Dunker’s 
figure of this supposed alga and Mantell’s Sphenopteris Sillimant ; 
it would seem, therefore, that the best course to follow is to regard 
both names as synonyms of Onychiopsis Mantelli. 
With regard to the species of Sphenopteris, S. Rémert and 
S. tenera, figured by Dunker, there can be little or no doubt that 
previous writers have correctly included them under Brongniart’s 
characteristic Wealden species. 
The species of Sphenopteris described and figured by Tate from 
the Geelhoutboon beds in the Uitenhage series of South Africa has 
not hitherto been compared to O. Mantelli. This South African 
form is compared by Tate? to Sphenopteris Jugleri, Ettingshausen 
(written in Tate’s paper ‘‘ Fu/geri’’), a species included in this 
Catalogue under Ruffordia Gépperti (Dunk.). There is such an 
obvious resemblance between S. antipodium and some of the 
pieces of O. Mantelli fronds from the Ecclesbourne beds, that it 
is impossible to point to any difference which would warrant the 
retention of Tate’s name. After looking at Tate’s type specimen 
in the Museum of the Geological Society, Burlington House 
(41s. Foreign Coll.), I have no hesitation in regarding it as an 
example of O. Mantelli. In the National Collection there are 
a few specimens of this plant from Africa, e.g. V. 2899 and 
V. 2401. In the descriptions and illustrations of North 
German specimens Schenk has added considerably to our know- 
ledge of this species, but he failed to recognize the fact, 
since pointed out by Nathorst, that one of his figured specimens 
of Sphenolepis Kurriana, Schenk, is in reality part of a fertile 
frond of O. Mantelli. One of the specimens figured by Schenk‘ as 
1 Paleontographica, vol. xix. p. 209. 
* Quart. Journ. Geol. Soe. vol. xxiii. 1867, p. 189, pl. vi. fig. 3. 
3 Paleontographica, vol. xix. pl. xxxviil. fig. 2. 
4 Loc. cit. pl. xxv. fig. 3. 
