ciENis. 235> 



1. Ctenis falcata, Lindley & Hutton. 



[Foss. Flor. vol. ii. pi. ciii. 1834.] 

 (PI. YIII. Kg. 2.) 



1828. Zamia longifoKa, Brongniart, Prodrome, p. 94. 



1829. Cycadites suleicaulis, Phillips, Geol. Yorks. p. 148, pi. vii. fig. 21. 

 1834. Ctenis falcata, Lindley & Hutton, Foss. Flor. pi. ciii. 



1838. Ctenis falcata, Sternberg, Flor. Vorwelt, vii. p. 163. 



1841. Zamites longifolia, Morris, Annals, vol. vii. p. 116. 



1845. Ctenis falcata, Unger, Sjn. plant, foss. p. 165. 



1848. Ctenis falcata, Bronn, Ind. Pal. p. 355. 



1849. Ctenis falcata, Brongniart, Tableau, p. 106. 



1850. Ctenis falcata, Unger, Gen. spec. foss. p. 307. 

 1854. Ctenis falcata, Morris, Brit. Foss. p. 6. 



1856. Ctenis falcata, Zigno, Flor. foss. Oolit. vol. i. p. 190, pi. xxiv_ 



figs. 1-3. 



1864. Ctenis falcata, Leckenby, Quart. Joiu'n. Geol. Soc. vol. xx. p. 76. 



1870. Pterophylliim falcatum, Schimper, Trait, pal. veg. vol. ii. p. 137. 



1874. Ctenis falcata, Schimper, ibid. vol. iii. p. 521. 



1875. Ctenis falcata, Phillips, Geol. Yorks. p. 218, pi. vii. fig. 21. 



1876. Of. Ctenis oHentalis, Heer, Flor. foss. Arct. vol. iv. (2), p. 105,. 



pi. xxii. fig. 2. 

 1892. Ctenis falcata, Fox-Strangways, Tab. Foss. p. 137. 

 1896. Ctenis falcata, Staub, Foldt. Kozl. vol. xxvi. p. 1. 



Frond pinnate ; the linear pinnas are attached obliquely or 

 almost at right angles to the sides of the rachis, and as regards 

 their attachment they resemble those of the genus Pterophyllum ;, 

 the long pinnse or segments, which reach a length of more than 

 10 cm., taper gradually towards an acuminate apex, which is 

 seldom preserved ; they are traversed by several parallel veins, 

 connected by frequent lateral anastomoses, which diverge slightly 

 in the broader basal region of the pinnse (PI. YIII. Pig. 2). At 

 the base of each pinna the lamina becomes broader, the upper 

 margin is bent slightly upwards on the rachis, and the lower 

 margin is strongly decurrent. The frond terminates in two pinnae 

 placed almost parallel to the long axis of the leaf. 



The name Zamia longifolia, used by Brongniart in his Prodrome 

 in 1828,' has been superseded by Ctenis falcata of Lindley & Hutton. 

 A good specimen of Ctenis from Cayton, near Scarborough, ia the 



Brongniart (28i),p. 94. 



