KLUKIA. 131 



1838. Pecoptens obtusifolia, Sternberg, Flor. Vorwelt, fasc. vii. p. 155. 



1848. Pecoptens exilis, Bronn, Ind. Pal. p. 915. 



1850. Cyatheites obtiaif alias, linger, Gen. spec. foss. p. 159. 



1851. Pecoptens exilis, Bunbury, Quart. Journ. Geol. Soc. vol. vii. p. 188. 

 1854. Pecopteris exilis, Morris, Brit. Foss. p. 15. 



1856. Pecopteris exilis, Zigno, Flor. loss. Oolit. vol. i. p. 144. 



1864. Pecopteris exilis, Leckenby, Quart. Journ. Geol. Soc. vol. xx. p. 76. 



1869. Pecopteris exilis, Schimper, Trait, pal. veg. vol. i. p. 536. 



1875. Pecopteris exilis, Phillips, Geol. Yorks. p. 210, pi. viii. fig. 16. 



1891. Klukia exilis, Raciborski, Engl. Jahrb. vol. xiii. p. 1. 



1892. Pecopteris e.rilix, Fox-Strangways, Tab. Foss. p. 132. 



1894. Klukia exilis, Seward, Proc. Phil. Soc. Camb. vol. viii. p. 197. 



K. exilis, Raciborski, Flor. Krakow, p. 165, pi. vii. fig. 13 ; pi. viii. 



figs. 1-3, 7(?), 8, and 9i ; pi. ix. figs. 1 and 2 (?) ; pi. xxvi. 



fig. 1 (?). 



K. exilis, var. i>arrifolia, ibid. p. 167 ; pi. viii. fig. 6 ; pi. xxvi. fig. 2. 

 K. acKtifolia, ibid. p. 168, pi. vii. figs. 10-12 and 18. 

 K. Phittipsn, ibid. p. 169, pi. viii. figs. 4 and 5 ; pi. vii. fig. 16. 



Type-specimen. ? York Museum. 



Frond tripinnate, of the Cladophlebis type ; the pinnae are 

 alternate and linear, lanceolate in form ; attached to the rachis 

 at a wide angle. The ultimate segments are short and linear, 

 with more or less hluntly rounded apices, seldom exceeding 5 mm. 

 in length ; the sporangia, which may reach a length of '5 mm., 

 are borne singly on the under side of the pinnules, forming a single 

 TOW on each side of the midrib. 



It is difficult to distinguish some of the sterile bipinnate fronds 

 of this type from the fern described by Lindley & Hutton as 

 Sphenopteris serrata. Nuthorst considers the two forms specifically 

 identical, but I believe that the latter fern should be included 

 in Neuropteris arguta of Lindley & Hutton. 



Kaciborski's figures of the specimens he refers to Klukia 

 acuti folia, K. exilis, and K. PJtiUipsi do not afford satisfactory 

 evidence of specific difference ; it is probable that the examples 

 so named are all referable to Phillips' species. 



There are several good examples of Klukia exilis in the 

 Leckenby Collection, Cambridge, and in the Museums of Man- 

 chester, Scarborough, and other places. 



40,557. PI. XVI. Fig. 7. 



A portion of a bipinnate fertile frond ; the narrow linear pinnae 

 are given off from the rachis at a wide angle. The pinnules, 



