584 



CYCADOPHYTAN FRONDS 



[CH. 



PSEUDOCTENIS. Seward. 



This genus^ was established for certain pinnate fronds agreeing 

 in habit with Ctenis sulcicaulis but distinguished by the almost 

 complete absence of any cross-connexions between the veins. 

 Some of the forms with narrow pinnae closely resemble species 

 of Zamites, the distinguishing feature being the decurrent lower 

 margin of the leaflets. Though such fronds might not unreason- 

 ably be included in Ctenis, it is more convenient on the analogy 

 of the occasional occurrence of Glossopteris fronds with very few 

 anastomoses to employ a distinctive designation. 



Fig. 627. Pseudoctenin eathiensis. (British Museum, 

 No. V. 2744; J nat. size.) 



Pseudoctenis eathiensis (Richards). 



Some of the specimens on which this species^, is founded were 

 originally figured by Miller* from Upper Jurassic strata in Scot- 

 land and afterwards named by Richards* Zamites eathiensis. 

 The general appearance of the fronds is very like that of Ctenis 

 sulcicaulis ; the pinnae vary in breadth from about 3 mm. to 

 1-5 cm. ; they are attached at right-angles or, in the apical region, 



1 Seward (IP) p. 691. ^ n,i^ p. 792, pis_ j^^ ^^^ ^^^^^ ^ 



' Miller (57) B. figs. 133, 13o. « Richards (84) p. 117. 



