THE JURASSIC FLOEA OF SUTHERLAND. 657 



As Halle points out in his recent paper on Sagenopteris, # it is not always possible 

 to distinguish between S. Nilssoniana (Brongn.) and S. Goeppertiana Zig. ; nor indeed 

 is the distinction between S. Phillipsi Brongn. and S. Nilssoniana by any means clear 

 in all cases, though the latter and older species has usually larger and broader leaflets. 

 The Wealden species S. Mantelli (Dunk.), as figured by ScHENKt and other authors, is 

 another variable type which presents a fairly close resemblance to S. Phillipsi, but the 

 leaflets tend to be shorter and broader. The separation by Moller} of Sagenopteris 

 leaflets from the Lower Jurassic of Bornholm into the two species S. rhoifolia 

 ( = S. Nilssoniana) and & Phillipsi does not appear to rest on adequate grounds, nor 

 is it clear why Raciborski § recognises the two species S. Phillipsi and S. Goeppertiana 

 in the material from the Lower Jurassic of Cracow. Sagenopteris Phillipsi was 

 widely spread in the Jurassic floras of Europe ; it has been recorded also from Jurassic 

 beds in North America, || and the specimens figured by Fontaine from Lower 

 Cretaceous strata of California as S. elliptica IF probably belong to the same species. 

 Nathorst ## describes an Antarctic specimen from Louis Philippe Land as possibly 

 identical with S. Phillipsi, and Yabe's species S. bilobata,ff from the Jurassic 

 of Korea, is perhaps an example of the same type. 



FILIGINEM 



1. Dipteridinae. 



Hausmannia, Dunker. 



One of the most interesting discoveries made by Dr G-tjnn is the presence of 

 Hausmannia in the Culgower flora. This generic name, employed in the wider sense in 

 which it is used by Richter JJ in his admirable monograph of the genus, includes both 

 the Wealden species on which Dunker founded the genus and the Jurassic species on 

 which Andrae §§ founded his genus Protorhipis. Hausmannia bears a close resemblance 

 in habit to the existing ferns Dipteris and Platy cerium, though the venation and soral 

 characters show it to be more nearly akin to Dipteris, a genus which has persisted 

 through the ages in the Indian and Malayan regions. 



Hausmannia dichotoma Dunk. (PI. I. figs. 14-17, fig. 19 ; PI. II. fig. 20.) 



1846. Dunker, Wealdenbildung, p. 12, pi. v. fig. 1. 



This species is represented by several specimens, many of which are fragmentary, 



though some (figs. 14, 15, PI. I. ; fig. 20, PI. II.) furnish striking examples of the deeply 



lobed fan-shaped fronds. The impression seen in fig. 20 bears a superficial resemblance 



to Ginkgo or Baiera, from which it is, however, distinguished by venation characters. 



* Halle (10). t Schenk (71), pi. x. fig. 5. % Moller (02). 



§ Raciborski (94), pi. xx. || Ward (05). IT Ward (05), p. 236. 



** Nathorst (04). +t Yabe (05), pi. iii. fig. 16. \% Richter (06). §§ Andrae (53). 



