192 WILLIAMSONIA. 



Although the pinnate fronds, which were named by Lindley & 

 Hutton Cyeadites pecten and C. pectinoides, haye never been 

 found in organic union with the type of Williamsonia described 

 by Nathorst as W. Lechenbyi,^ there can be little, if any, doubt 

 that the latter is the flower of the plant which bore the well- 

 known pinnate leaves long known by Phillips' name Pterophyllum 

 pecten. The constant association of the small species of Williamsonia 

 with these fronds is in itself a strong argument for their specific 

 identity. The extremely variable form of the fronds is at once 

 apparent if we examine carefully the numerous examples of 

 this species in the various British and Contiuental collections. 

 In addition to the specimens in the British Museum illustrating- 

 the frequent association of various forms of Williamsonia pecten on 

 one piece of shale, equally instructive examples may be seen in 

 the Museums of Scarborough, York, and Manchester. One slab 

 of rock in the Scarborough Museum shows about thirty fronds- 

 in which there is considerable variation in the breadth of the 

 pinnsB. Specimens in the Manchester Museum also demonstrate 

 the variability of the species : one frond 24 cm. in length bears- 

 pinnse with bluntly rounded bases and the upper basal edge 

 distinctly lobed (auriculate) (cf. V. 3516, etc.), and in close 

 association with this occur other examples in which the pinnae 

 are smaller and without a basal lobe. The fossils originally 

 named by Brongniart Zamia GoMitsi, and afterwards figured by 

 Saporta as Otozamites Goldicsi,'' are, I have no doubt, specifically 

 identical with Williamsonia pecten ; but the latter name is very 

 much better known, and the form of frond to which th& 

 designation pecten was first applied represents the more t3'pical 

 form. A Liassic Otozamites described by Lignier from Normandy 

 as 0. Apperti ^ may also be compared with Williamsonia pecten ; 

 the pinnsB are slightly lobed at the base, and, as Lignier points 

 out, they resemble Otozamites GolAimi. 



An important question is the affinity of several Cycadean fronds 

 ii'om Indian beds, which Feistmantel included in the genus 

 PtilopJiyllum, proposed by Morris iu 1 840, with the English fronds 

 usually referred to Pterophyllum, and now spoken of as Williamsonia 



' Nathorst (80^). 



2 Saporta (75), pi. xx. fig. 1. 



3 Lignier (95), p. 22. 



