292 PAGIOPHYLLirM. 



a triangular apical portion, at right angles to the sporophyll axis,, 

 which is characterized by a median vertical keel. 



As the list of synonyms shows, this fairly common species has 

 been referred to various genera ; that it is a Conifer there is no 

 longer any doubt, both male and female cones having been found 

 in organic connection with the vegetative branches. It is, however, 

 a little difficult to decide in which family of the Coniferao 

 Pagiophyllum Williamsoni should be included. The form of the 

 leaves and the general appearance of the branches at once suggest 

 a comparison with certain species of Araucaria, e.g. Araucaria 

 excelsa, It. Br., the Norfolk Island pine, but such knowledge as 

 we possess as to the structure of the cones does not enable us 

 to decide the question of Araucarian affinity. The male flowers 

 are not sufficiently well preserved to afford any decisive evidence 

 as to the number of the pollen-sacs or their manner of attachment 

 to the stamens ; their external form agrees closely with that of the 

 male flowers of various types of the Abietinese, and in itself does 

 not supply confirmatory evidence of a close relationship with 

 Araucaria. 



The present species bears a close resemblance to Pagiophyllum 

 peregrinum (L. & H.), of Liassic age, described from the English 

 Lias and elsewhere. Home of the coniferous twigs described under 

 Hcer's generic name Elatides are very similar to Pagiophyllum 

 Williamsoni ; as Hecr points out, the Siberian Jurassic species 

 Elatides falcata 1 resembles the English type, but the leaves of the 

 latter are much broader at the base. The distinction between the 

 two genera Pagiophyllum and Elatides is by no means well marked, 

 and either generic term might be used as a suitable designation for 

 certain Mesozoic coniferous twigs. 



Several specimens of this species are included in the collections 

 of Whitby, Scarborough, Cambridge, and elsewhere ; both the 

 male and female cones are not infrequently found in organic 

 connection with the vegetative shoots. 



13,516. PI. X. Fig. 3. 



This specimen illustrates the characteristic falcate leaves and 

 the form of the female cones borne on slender lateral branches. 



1 Heer (77), vol. iv (2), p. 79, pi. xiv. %. 6. 



