DIOONITES. 239 



Ctenopteris insignis, Font.. 1 may be specially compared with the 

 English type. It is worthy of note that some of the frond 

 fragments described by Feistmantel from the Upper Mesozoic beds 

 of Queensland as Thinnfeldia odontopteroides (Morr.) should be 

 referred to Ctenoza mites. 2 



Genus DIOONTTES, Miquel. 



[Tijdsch. Wis. Nat. Wet. vol. iv. p. 205, 1851.] 



The solitary specimen which I have referred to this genus 

 does not afford entirely satisfactory evidence as to the precise 

 manner of attachment of the pinnae to the rachis, but it is 

 probably better to adopt the designation Dioonites than any other 

 generic name. I have elsewhere given a comprehensive diagnosis 

 of this genus. 3 



Dioonites Nathorsti, sp. nov. 



Type-specimen. "Woodwardian Museum, Cambridge (Leckenby 

 oll., No. 222). 



Frond pinnate ; the pinnae are given off from a fairly stout rachis 

 at an acute angle. The pinnae are narrow and linear, 3-4 mm. 

 wide, and reaching a length of 8 cm. ; they are attached by the 

 whole of the base, which is slightly wider than the rest of the 

 pinnae ; the pinnae are tapered gradually to an acuminate apex, 

 and are traversed by about eight parallel veins. 



On the back of the type-specimen Nathorst has written: "This 

 is a new species, belonging to some genus allied to Pterophyllum." 

 In the best specimen, which is probably seen from the upper 

 side, the rachis has a length of 14*5 cm. ; the pinnae appear to be 

 attached laterally, but this is, I believe, due to the exposure 

 of the dorsal surface of the frond. The frond must have reached 

 -a considerable length, and the breadth, which is fairly uniform 

 in the portion preserved, measures approximately 15-16 cm. 



1 Fontaine (89), p. 156, pis. lxi.-lxiii. 



2 Feistmantel (90), p. 101, pi. xxix. figs. 1 and 5. 



3 Seward (95), p. 41. 



