Worsdell . — The Structure and Origin of the Cycadaceae. 155 
seed of Lyginodendron , as also in that of Neuropteris heterophylla , the outer 
integument is probably represented by the detached cupule, while the inner 
integument itself is a hard sclerotic envelope. In Trigonoccirpus there was 
an outer fleshy layer concrescent with an inner bony envelope, just as in 
modern Cycads. The same was also probably the case with Stephano- 
spermum. 
In Taxus the fleshy layer is detached in the form of an aril. Hence 
I am led to regard the outer fleshy layer in the ovule of Cycads as 
representing the outer integument, and the sclerotic layer and inner soft- 
celled tissue as together constituting the inner integument. 
Bibliographical. 
Arber : On some new species of Lagenostoma. Proc. Roy. Soc., ser. B, vol. lxxvi, 1905. 
Bary, A. de : Notizen iiber die Bliithe einiger Cycadeen. Bot. Zeit., 1870. 
: Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns. 
1884. 
Benson, M. : On Telangium Scotti. Ann. Bot., vol. xviii, 1904. 
Bertrand and Renault : Remarqnes sur les faisceaux foliaires des Cycadees actuelles et sur la 
signification morphologique des tissus unipolaires diploxyles. Arch. Bot. du Nord, vol. ii, 
1882-6. 
— : Recherches sur les Poroxylons, Gymnospermes fossiles des terrains 
houillers sup^rieurs. Id. 
Bower : On the Comparative Morphology of the Leaf in Vascular Cryptogams and Gymnosperms. 
Phil. Trans., vol. clxxv, 1884. 
Braun : Die Frage nach der Gymnospermie der Cycadeen, erlautert durch die Stellung dieser 
Pamilie im Stufengang des Gewachsreiches. Monatschr. k. preuss. Akad. d. Wiss., 1875. 
: Ueber zwei von Hildebrandt angefiihrte Cycadeen nebst Bemerkungen iiber einige andere 
Cycadeen. Sitzber. Ges. naturf. Freunde zu Berlin, 1876. 
Brongniart, Ad. : Recherches sur l’organisation des tiges des Cycadees. Ann. d. Sc. Nat., ser. 1, 
vol. xvi, 1829. 
* : Note sur un nouveau genre de Cycadee du Mexique. Ann. d. Sc. Nat., ser. 3, 
vol. v, 1846. 
: Les graines silicifiees. Paris, 1881. 
Buckland: On the Cycadeoideae, a Family of Fossil Plants found in the Oolite Quarries of the 
Isle of Portland. Geol. Trans, of London, ser. 2, vol. ii, 1828. 
Capellini and Solms-Laubach : I tronchi di Bennettitee dei musei italiani. Mem. d. R. Accad. 
d. Sc. d. Istituto di Bologna, ser. 5, vol. xii, 1392. 
Carruthers : On some Cycadean Fruits from Secondary Rocks of Britain. Geol. Mag., vol. iv, 
1867. 
: On Beania , a new Genus of Cycadean Fruits from the Yorkshire Oolites. Geol. 
Mag., vol. vi, 1869. 
: On Fossil Cycadean Stems from the Secondary Rocks of Britain. Trans. Linn. Soc., 
vol. xxvi, 1870. 
