1 54 SPHENOPTERIS. 



2. Sphenopteris Williamson!, Brongniart. 



[Hist. veg. foss. p. 177, pi. xlix. figs. 6-8, 1828.] 

 (PL XVII. Figs. 1 and 2.) 



1828. Sphenopteris Williamsonis, Brongniart, Hist. veg. foss. p. 177, pi. xlix. 



figs. 6-8. 



? 8. denticulata, ibid. pi. Ivi. fig. 1. 

 S. Williamsonis, Brongniart, Prodrome, p. 50. 



1829. Splienopteris digitata, Phillips, Geol. Yorks. p. 147, pi. viii. fig. 6. 

 1834. Sphenopteris Williamsonis, Lindley & Hutton, Foss. Flor. pi. cxxxi. 

 1836. Hymcnophyllites Williamsonis, Gb'ppert, Foss. Farrn. p. 259. 

 1838. Ehodea Williamsonis, Sternberg, Flor. Vorwelt, fasc. vii. p. 110. 



1848. Hymcnophyllites Williamsonis, Bronn, Ind. Pal. p. 602. 



1849. Sphenopteris Williamsonis, Brongniart, Tableau, p. 105. 



1850. Hymcnophyllites Williamsonis, Unger, Gen. spec. foss. p. 130. 

 1854. Hymenophyllites Williamsonis, Morris, Brit. Foss. p. 10. 



1856. Hymcnophyllites Williamsonis, Zigno, Flor. foss. Oolit. vol. i. p. 89. 

 1864. Hymcnophyllites Williamsonis, Leckenby, Quart. Journ. Geol. Soc. 



vol. xx. p. 76. 

 1869. Sphenopteris (Hymcnophyllites} Williamsonis, Schimper, Trait, pal. 



veg. vol. i. p. 410. 



1875. Sphenopteris Williamsonis, Phillips, Geol. Yorks. p. 217, pi. viii. fig. 6. 

 1892. Sphenopteris Williamsonis, Fox-Strangways, Tab. Foss. p. 135. 



Type-specimen. Brongniart' s types in the Paris lluseum ('?). 

 Type of Lindley & Hutton in the Scarborough Museum. 



Frond ? tripinnate ; the rachis slender and winged, bearing short 

 acuminate pinnae attached at an acute angle ; the pinnules are 

 deeply dissected into narrow linear and forked ultimate segments. 



There is not sufficient reason for following the example of some 

 authors and using the generic name Hymenophyllites for this species ; 

 we know nothing as to the character of the sori or sporangia. 



39,281. PI. XVII. Fig. 2. 



The drawing represents a portion of a pinna 7 cm. long, bearing 

 deeply dissected pinnules with narrow ultimate segments. The 

 finer segments are traversed by a single vein, and the general 

 appearance of the specimen suggests a fern with a thin or almost 

 filmy texture ; this thin brown filmy appearance is misleading and 

 need not necessarily point to an originally thin lamina. There is- 



