2. Cypassis eucolpos, n. sp.
Inner cortical shell thick walled, with regular, circular pores, twice as broad as the bars (without hexagonal frames); nine to ten on the half meridian of each chamber, fifteen to seventeen on its half equator. Outer cortical shell very thin, with smooth surface, and very small, irregular, roundish pores, twice to three times smaller than those of the inner shell. Distance between the two cortical shells about one and a half times the diameter of the inner medullary shell, which, like the outer, is spherical. (The inner cortical shell resembles that of Cannartiscus amphiconiscus, Pl. 39, fig. 19, but without polar tubes.)
Dimensions.—Main axis of the external cortical shell 0.2, of the internal 0.15; greatest breadth of the former 0.16, of the latter 0.12; pores of the outer 0.002, of the inner 0.006, bars 0.003.
Habitat.—South Atlantic, Station 319, surface.
Subgenus 2. Didymocyrtis, Haeckel (1862).
Definition.—Surface of the cortical shell thorny or spiny.
3. Cypassis entomocora, Haeckel.
Haliomma didymum, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 83.
? Haliomma amphisiphon, Ehrenberg, 1844, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 267.
Ommatospyris entomocora, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, pp. 66, 74.
? Ommatocampe trinacria, Stöhr, 1880, Palæontogr., vol. xxvi. p. 90, Taf. ii. fig. 1.
Didymospyris entomocora, Haeckel, 1881, Prodromus.
Didymocyrtis entomocora, Haeckel, 1862, Monogr. d. Radiol., p. 445.Inner cortical shell thick walled, with regular, circular pores, twice as broad as the bars (without hexagonal frames); eight to nine on the half meridian of each chamber, ten to eleven on its half equator. Outer cortical shell thin walled, with regular, circular pores like those of the inner. Distance between the two cortical shells equals about twice the diameter of one pore (or the short axis of the lenticular double medullary shell). Surface covered with short conical spines (in the figure of Ehrenberg broken off).
Dimensions.—Main axis of the external cortical shell 0.2, of the internal 0.15; greatest breadth of the former 0.13, of the latter 0.1; pores of the outer 0.005 to 0.01, of the inner 0.01, bars 0.004; length of the surface spines 0.005 to 0.01.
Habitat.—Fossil in the Tertiary rocks of Barbados, Bermuda, and Sicily (Caltanisetta); also living in the greatest depth of the Pacific, Stations 268, 225, depth 2900 to 4475.
4. Cypassis puella, n. sp. (Pl. 39, fig. 13).
Internal cortical shell thin walled, with irregular, circular pores of very different size, once to four times as broad as the bars; fourteen to fifteen on the half meridian of each chamber, eighteen
