XXVIl] 



CTENOPTERIS 



549 



Frond bipinnate, broad rachis giving ofF branches at an acute angle ; 

 pinnules broadly linear, slightly falcate, with several slightly divergent 

 forked veins. 



A frond very similar to the Lower Lias specimen from 

 Dorsetshire represented in fig. 362 was described by Leckenby 

 as Ctenis Leckenhyi (Bean MS.) from the Inferior Oolite of 

 Yorkshire'- Leckenby recognised the possibility of a Cycadean 



Fiu. 362. Ctenopteris eyeadea, Brongn. (^ nat. size.) From a specimen in 

 the British Museum. [M.S.] 



affinity, but regarded the bipinnate habit as an objection. The 

 branched fronds of the Australian Cycad Bowenia supply an 

 answer to this objection. Several good examples of Ctenopteris 

 cycadea are figured by Schenk^ from Ehaetic rocks of Persia. 

 Zeiller's Tonkin Rhaetic species, G. Sarrani', affords a striking 

 illustration of the difficulty of drawing a clear line of separation 

 between Ctenopteris and some species of Thinnfeldia. 



1 Leckenby (64) A. PI. x. fig. 1 ; Seward (04) p. 36. 



2 Sohenk (87). ' Zeiller (03) Pis. vi.— viii. 



