XXXIX] PSETJDOCTENIS 585 



may be almost parallel to the rachis. The longest pinna recorded 

 is 17 cm. and the lamina tapers to a slender apex; the veins are 

 parallel and occasionally forked, but cross-connexions are rare. 

 The partially petrified rachis of one specimen showed hypo- 

 dermal stereome and some secretory canals as in recent Cycads. 

 The specimen from Wealden rocks near Hastings (fig. 627), 

 originally described as Zamites sp.^, is probably specifically 

 identical with Pseudoctenis eathiensis. The South African Wealden 

 species, originally described by Tate as Palaeozamia Rubidgei^, 

 agrees closely with Pseudoctenis and is probably an example of 

 that genus. This type bears a close resemblance in the form 

 of the frond to Ctenophyllum grandifolium Font.' and C. Wardi^ 

 Font, from American Trias and Jurassic rocks respectively. 

 Pseudoctenis crassinervis Sew.^ is another Scotch form with coarser 

 veins. 



A frond very similar in habit to P eathiensis is represented 

 by Pseudoctenis ensiformis HaUe® from the Jurassic strata of 

 Graham Land originally referred by Nathorst to Pterophyllum. 

 An examination of the type-specimen in the Stockholm Museum 

 revealed its resemblance to the Scotch species P. eathiensis: 

 a single anastomosis was noticed in one of the pinnae. The 

 broadly ensiform obtuse pinnae, reaching a length of 7 cm. with 

 a maximum 'breadth of 3 cm. at their expanded bases, vary in 

 breadth and are attached at right-angles to a slender rachis. 

 The veins, I— 1-5 mm. apart, are parallel and strong. The varying 

 breadth of the pinnae irrespective of their position on the rachis 

 is a distinctive feature. Halle draws attention to a resemblance 

 of this Antarctic species to Ctenophyllum latifolium Font, a Potomac 

 type referred by Berry' to the genus Ctenopsis on the rather slender 

 ground that the veins are arranged in pairs. Berry in a footnote 

 expresses the opinion that Ctenopsis is very closely related to or 

 possibly identical with Pseudoctenis. 



If the bases of the pinnae in the specimen of P ensiformis 

 figured by Halle are complete, as they appear to be, the frond 



1 Seward (95) A. p. 89, fig. 5. 



2 Tate (67) PI. v. fig. 3 ; Seward (03) B. PI. v. fig. 3. 



" Fontaine (83) B. Pk. xxxix. — xlii. * Fontaine in Ward (05) B. PI. xxiii. 

 ■^ Seward (ll^) Pis. iv., vn. " Halle (13^) p. 51, PL vi. fig 8. 



' Berry (11) p. 349. 



