198 



•WILLIAMSONIA. 



39,284. PI. III. Figs. 4 and 5. 



Fig. 4 represents a small piece of a frond wMch. occurs om 

 a large slab of rock in association with between tbirty and forty 

 other examples, of wliicli tbe pinnse vary considerably in size and 

 shape. The upper edge of the base of the long and narrow pinnse 

 shown in Fig. 4 is slightly lobed, but in some of the pinnse the 

 auriculate base is much more evident. The veins are somewhat 

 spreading at the base, and inclined at an oblique angle to the upper 

 margin of the pinnse, but their general course is parallel to the 

 long axis of the segments. Cf. Pterophyllum rigidum as figured 

 by Andrae,^ and Text-fig. 31. 



Fig. 33. — The base of a frond of Willianuonia pecten (Phill.). 

 No. 13,515. (Nat. size.) 



In Fig. 5, PI. III. we have a form of frond similar to that 

 shown in Fig. 1, but this specimen no doubt represents a young 

 leal which is not fully expanded, and in which the segments 

 are slightly imbricate in their arrangement, as in the fronds of 

 many recent Cycads. Similar examples of young and narrow 

 fronds, showing an imbricate vernation, may be seen in thes 

 Museum of Practical Geology, Jermyn Street, London, and in 

 the Newcastle Collection. Some of the fronds associated with 

 the figured specimens are of the type shown in Fig. 2 ; others are 



' Andrae (53), pi. xi. fig. 1. 



