518 



CYCADOPHYTAN FRONDS 



[CH. 



paper Halle^ repeats the view that the decurrence of the pinnae 

 by their lower edges is an important distinguishing feature of 

 Ptilophyllum, thus agreeing with Feistmantel whose illustrations 

 appear to be confirmatory. The drawings in Feistmantel s 

 memoirs are, however, misleading and in some cases incorrect. 

 An examination of a photograph of Morris's type-specimen of 

 P. cutchense led Halle to conclude that the two edges of the pinna- 

 base bend downwards on joining the rachis as described by 

 Feistmantel. This feature is not shown in the drawing repro- 

 duced in fig. 591 : it is clear that either the drawing is incorrect 



Fig. 591. Part of the type-specimen of Ptilophyllum cutchense 

 Morris. (British Museum; x 3.) 



or that there has been some mistake in the interpretation of the 

 photograph. Through the courtesy of Dr Halle I have been 

 able to examine the actual print: when viewed in its correct 

 position the two edges of the pinnae appear to bend down as 

 described by Halle, but if it is examined in the reverse position 

 the lower angle of the pinnae is seen to be slightly rounded as in 

 fig. 591, the apparent decurrence being due to a confusion between 

 the appressed lower edge of one pinna, which is faintly shown, 

 and the stronger downward trend of the upper edge of the pinna 

 next below. The upper edges of the pinnae are more prominent 



1 Halle (132). 



