52 
Thoday. — Anatomy of the Ovule and Seed in 
and strongly lignified down to the level of the shoulders of the seed. When 
the beak or basal part of the tube is broken off from the upper part, some 
of the closing tissue of the stopper is generally dragged out, leaving a cavity 
in the bottom of the stopper. 
An attempt is made to compare more closely than before the series of 
seeds belonging to the different species of Gnetum with some of those of the 
Bennettitales. Williamsonia scotica, with its simple plan, is compared with 
a young seed of Gnetum , and new light seems to be thrown on the complex 
structure of Cycadeoidea and Bennettites Morierei by the mature seed of 
Gnetum Gnemon. 
The greater part of this work was done in the Manchester University 
Botanical Laboratory. My thanks are due to my husband, Professor 
D. Thoday, for his assistance in the preparation of the text-figures. 
Literature cited. 
Berridge, E. M. : On some Points of Resemblance between Gnetalean and Bennettitalean Seeds. 
New Phyt., x, 1911. 
Lignier, O. : Vegetaux fossiles de Normandie. Structure et affinites du Bennettites Morierei. 
Bull, de la Soc. Linn, de Nor., 1894. 
. l c Bennettites Morierei. Bull, de la Soc. Bot. de France, vol. lviii, ser. 4, 1911. 
Lotsy, J. R. : Contributions to the Life-history of the Genus Gnetum. Ann. Jard. Bot. Buit. (2), 
i, 1899. 
Pearson, H. H. W. : Notes on the Morphology of certain Structures concerned in the Reproduction 
of the Genus Gnetum. Trans. Linnean Soc., viii, 1915. 
Seward, A. C. : A Petrified Williamsonia from Scotland. Phil. Trans. Roy. Soc., B., cciii, 1912. 
Sykes, M. G. : The Anatomy and Morphology of the Leaves and Inflorescences of Welwitschia 
mirabilis. Ibid., cci, 1912. 
Thoday, M. G. (Sykes, M. G.) : The Female Inflorescence and Ovules of Gnetum africanum , 
with Notes on Gnetum scandens. Ann. Bot., xxv, 1911. 
— — — and Berridge, E. M. : The Inflorescences and Flowers of 
Ephedra. Ibid., xxvi, 1912. 
Wieland, G. R. : A Study of some American Fossil Cycads. Part V. Further Notes on Seed 
Structure. Amer. Journ. of Science, xxxii, 1911. 
: Ditto. Part VI. On the Smaller Flower Buds of Cycadeoidea. Ibid., xxxiii, 
191 2. 
: On the Williamsonian Tribe. Ibid., xxxii, 1911. 
: American Fossil Cycads. Carnegie Institute. Pt. I. 1906. 
: Ditto. Pt. II. 1916. 
