44 ONTCHIOPSIS. 



"Geology of Sussex," refers to the method of branching in 8. 

 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 fasus, Dunker, as a fragment of 0. 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 Sillimani 

 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. Romeri 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 0. Mantelli. This South African 

 form is compared by Tate 2 to Sphenopteris Jugleri, Ettingshausen 

 (written in Tate's paper " Fulgeri "), a species included in this 

 Catalogue under Ruffordia Gopperti (Dunk.). There is such an 

 obvious resemblance between S. antipodium and some of the 

 pieces of 0. 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 

 (41j. Foreign Coll.), I have no hesitation in regarding it as an 

 example of 0. Mantelli. In the National Collection there are 

 a few specimens of this plant from Africa, e.g. V. 2399 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, 3 is in reality part of a fertile 

 frond of 0. Mantelli. One of the specimens figured by Schenk 4 as 



1 Palyuontographica, vol. xix. p. 209. 



2 Quart. Journ. Geol. Soc. vol. xxiii. 1867, p. 139, pi. vi. fig. 3. 



3 Palaeontographica, vol. xix. pi. xxxviii. fig. 2. 

 * Loc. cit. pi. xxv. fig. 3. 



