Cortical shell thin walled, slightly rough, with regular, circular pores, twice as broad as the bars; twelve to fifteen on the half equator. Proportion of both axes = 4 : 3. Both medullary shells spherical.
Dimensions.—Major axis 0.12, minor 0.09; pores 0.006, bars 0.003; diameter of the medullary shells 0.06 and 0.03.
Habitat.—Pacific, central area, Station 273, depth 2350 fathoms.
5. Prunulum crenatum, Haeckel.
? Haliomma crenatum, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 36.
Actinomma crenatum, Stöhr, 1880, Palæontogr., vol. xxvi. p. 94, Taf. iii. fig. 3.
Caryolithis crenata, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 43.
Cortical shell thick walled, slightly rough or thorny, with small, regular, circular pores, of the same breadth as the bars; sixteen to eighteen on the half equator. Proportion of the two axes = 4 : 3. Both medullary shells ellipsoidal. (The figure of Stöhr represents exactly the fossil form, as I have observed it myself in the Caltanisetta rocks, whilst the figure of Ehrenberg is inaccurate and doubtful. The same form, somewhat variable in size and in the number of the pores, I have also observed in the Pacific ooze.)
Dimensions.—Major axis 0.14 to 0.17, minor 0.1 to 0.13; pores and bars 0.006; main axes of the medullary shells 0.09 and 0.03.
Habitat.—Fossil in the Tertiary rocks of Sicily (Grotte and Caltanisetta); living in the Central Pacific, Station 268, depth 2900 fathoms.