RADIOLARIA.
Lower Cambrian.—David, T. W. E. and Howchin, W. Proc. Linn. Soc. New South Wales, vol. XXI. 1897, p. 571.
Devonian.—David, T. W. E. Proc. Linn. Soc. New South Wales, vol. XXI. 1897, pp. 553-570. Hinde, G. J. Quart. Journ. Geol. Soc., vol. LV. 1890, pp. 38-64.
Upper Cretaceous.—Hinde, G. J. Quart. Journ. Geol. Soc., vol. XLIX. 1893, pp. 221-226.
[CHAPTER VII.]
FOSSIL SPONGES, CORALS AND GRAPTOLITES.
SPONGES.
Characteristics of Sponges.—