524 Scientific Proceedings, Royal Dublin Society. 



circular in outline, with a projecting ring-like border, pronounced below and 

 passing off upwards into a sloping ledge, which may be regarded as part of 

 the leaf-field cushion. 



The stem surface of B. Tciltorhense shows a finely and longitudinally striate 

 epidermis. The direction of these strise is disturbed by the leaf-scar's 

 position. In addition the stem may show a marked fluting or ribbing 

 which is connected with the parichnos and bundle-strands, but possibly also 

 with internal sclerotic bands. The calamitoid appearance of such stems is 

 increased by the presence of horizontal or transverse ridges or zones which 

 are, unlike the longitudinal ridges, coincident with the surface leaf-scars, 

 and suggestive of nodal diaphragms. 



B. kiliorkense bifurcated at its base to form the Stigmaria rhizomatous 

 stage carrying numerous branching vascular root-like appendages. The 

 cone is terminal, and carried on its broad (hollow ?) axis numerous whorls of 

 sporophylls, of which the megasporophylls are the ones at present best 

 known. Each bore on its enlarged basal part some twenty more or less 

 rounded megaspores, 1 mm. in diameter. Certain sporophylls with thick 

 irregularly rugose surfaces appear to be the male sporophylls, the microspores 

 being 0-5 mm. in diameter. 



Bothrodendron offers marked calamitoid features, which show it to be 

 nearer the common ancestral type of the Lepidophyta and Equisetaceae 

 (Artioulatse) than either Lepidodendron or Sigillaria. 



Bibliography. 



1. Forbes, E. : On the Fossils of the Yellow Sandstone of the South of Ire- 



land. British Association Eeport, London, 1853 (Belfast Meeting, 

 1852), p. 43. Further references are given in my paper, " Is 

 Archseopteris a Pteridosperm ? " Scient. Proc. Eoy. Dublin Soc. 

 (N.S.), vol. xiii, 1911. 



2. Haughton, S. : On Cyclostigma, . . . Plates XIV -XVII., Journal Eoy. 



Dublin Soo., vol. ii, 1859, p. 407. Haughton's paper appeared 

 also in the Annals and Magazine of Natural History (vol. v, 3rd 

 series), but without the illustrations. 



3. Griffith, E., and A. Brongniart : Journ. Geo!. Soc, Dublin, vol. vii, 



1857, p. 287. 



4. Journ. Eoy. Dublin Soc, vol. i, 1858, p. 313. 



5. Heer, 0. : 1. Quart. Journ. Geol. Soc, vol. xxviii, 1852. 2. Fossile- 

 Flora d. Baren-Insel, 1871. 



