522 CYCADOPHYTAN FRONDS [CH. 



Otozamites is the name employed by Halle for fronds with 

 pinnae having contracted, asymmetrical and auriculate, bases, 

 the anterior lobe being more developed than the posterior. The 

 asymmetry of the pinna-base is considered an essential feature. 

 As Halle states it is very difi&cult in some instances to draw a 

 distinction between Otozamites and Ptilophyllum. As used in 

 this chapter Otozamites signifies fronds with pinnae characterised 

 by an auriculate base, a lamina usually broader than in Ptilophyl- 

 lum, and by more spreading veins (fig. 604). The not infrequent 

 occurrence of auriculate pinnae on fronds (fig. 603, A) which 

 cannot be separated from typical examples of P. pecten illus- 

 trates the narrow dividing line as regards the form of the pinna- 

 base between Ptilophyllum and Otozamites. The Indian species 0. 

 Hislopi (fig. 589) and 0. ahbreviatus, to which Halle refers some 

 Antarctic fronds, cannot be distinguished from the Enghsh P. 

 pecten or Feistmantel's and Morris's Indian fronds described as 

 P. cutchense and P. acutifolium : these forms are therefore included 

 in Ptilophyllum. 



Ptilophyllum (Williamsonia) pecten {Phillips). 



This designation is employed in a wide sense for a group of 

 fronds exhibiting a considerable range in size, in the relative 

 breadth and length of the linear pinnae, and in other features. 

 Under P. pecten are included (i) the English fronds from Yorkshire 

 first described by Phillips'- as Cycadites pecten and C. pectinoides, 

 the former from the Middle shale, the latter from the Lower shale 

 of the Yorkshire coast, together with the Stonesfield slate speci- 

 mens named by Sternberg^ Polypodiolites pectiniformis (fig. 595) 

 and by Brongniart^ and Lindley and Hutton* Zamia pectinata; 

 (ii) the Indian specimens already considered and (iii) numerous 

 examples recorded under different names from Jurassic strata 

 in many countries. Fronds from the Yorkshire coast named by 

 Brongniart^ Zamia Goldiei, though regarded by some authors as 

 examples of Otozamites, are probably referable to P. pecten. 



1 PhiUips (29) A. PI. VII. fig. 22; PI. x. fig. 4. 



'' Sternberg (23) A. PI. xxxiii. fig. 1. For other references, see Seward (00) B. 

 p. 190; (04) B. p. 106. 



^ Brongniart (28) A. p. 94. 



" Lindley and Hutton (35) A. PI. 172. = Brongniart (28) A. p. 94. 



