Spongocyclia cycloides, Haeckel, 1862, Monogr. d. Radiol., p. 469, Taf. xxviii. fig. 1.
Spongy disk on both sides plain, in the central part with five to ten concentric, circular rings, in the peripheral part quite irregularly and densely spongy. Meshes twice to four times as broad as the bars.
Dimensions.—Diameter of the disk 0.1 to 0.2, of the meshes 0.003 to 0.006.
Habitat.—Mediterranean (Messina), North Atlantic (Canary Islands).
7. Spongodiscus spongocyclia, Haeckel.
Spongocyclia triangularis, Stöhr, 1880, Palæontogr., vol. xxvi. p. 119, Taf. vii. fig. 5.
Spongy disk lenticular, in the thicker central part with eleven to twelve circular, concentric rings, in the thinner, peripheral zone irregularly spongy. Meshes twice to four times as broad as the bars. (The triangular form in the specimen figured by Stöhr is accidental, produced by the broken margin.)
Dimensions.—Diameter of the disk 0.2 to 0.3, of the meshes 0.006 to 0.008.
Habitat.—Fossil in Tertiary rocks of Barbados (Haeckel) and Sicily (Stöhr).