76 



MISS NELLIE BANCEOET ON SOME 



J 



The distribution of sclerencliyma in connection with the vascular bundles in 

 TtilopJiyllum and Dictyozamites is not clear, though there is evidently a much 

 smaller amount than in the cycadeoidean type figured by "Wi eland. (With regard 

 to the surface-features of the leaves, see Section II. " Methods.") 



ii. Fructifications. 



WiLLIAMSONIAN TYPE 



Block II. shows a Williamsonia-like fructification referred by Feistmantel, as already 

 mentioned, to Williamsonia gigas, Carruth., on account of the large number of bracts 

 surrounding it (PL 7. fig. 2; cf. 4, Taf . 2, figs. 1, 2, & 3; Taf. 3, figs. 1 6 & 4). 



■ 



The specimen, although apparently poorly preserved, was sectioned longitudinally and 

 transversely. The transverse section reveals a central mass of petrified tissue surrounded 

 by the transverse sections of the bracts, between which and the central structure is 

 matrix material (PI. 7. fig. 3). The bracts show seven vascular bundles as in the case 

 of the leaf-bases surrounding the stem to be described in the next sub-section. The 

 bundles are embedded in a ground-mass, having a broad peripheral band of sub- 

 epidermal sclerencliyma (see under " Stems " for further description). In places there 

 are indications of hairs between the bracts enclosing the central structure ; in this 

 respect, and also in the structure of the bracts, there is agreement with a Williams onian 

 female fructification from the Upper Jurassic of Scotland, described by Prof. Seward at 

 a meeting of the British • Association, 1911. No indications of male organs can be 

 detected in the Indian specimen. The central mass consists of cellular tissue, the 

 arrangement of which is suggestive, in spite of its indefiniteness, of transverse sections 

 of seed-stalks and interseminal scales, as shown by Wieland for Cycadeoidea (PI. 9. 

 fig. 10 ; cf. 36, pi. 8. fig. 6 ; pi. 10. figs. 14 & 16 ; and 37, p. 119, fig. 61). Owing to 

 lack of structure at the edge of the central portion it is impossible to determine whether 

 the transverse section was taken in or below the ovule-bearing region. 



The longitudinal section of the fructification is useless from a structural point of 

 view. In the extreme upper part of the central mass, however, the oiled cut surface 

 corresponding to the longitudinal section shows the ends of its vertically -running 



* 



constituents, the appearance being suggestive of the presence of interseminal scales and 

 . ovules (PI. 7. figs. 4 & 5). 



In spite of the meagre evidence aflbrded by this petrifaction, its similarity to 

 Seward's Williamsonia is sufficient to support its reference to the " W^illiams onian 

 type " of fructification, this being regarded as of Bennettitalean affinities on account 

 of the close correspondence to such forms as Bennettites Gibsonianus, Carruth. 



Block II. shows the moulds of bract-like structures and the reverse of the bract- 

 bases. Below these, and slightly to one side, is a raised mass, apparently of silicifled 

 wood, probably belonging to the axis which bore the bracts (PL 7. fig. 1). The 

 arrangement of the whole structure suggests that it represents part of a bract-bearing 

 fructification axis, referable to the Williamsonian type. , The James Yates collection of 



