Page:Scientific results HMS Challenger vol 18 part 1.djvu/574

366 11. Cyphonium ceratospyris, Haeckel.

Didymocyrtis ceratospyris, Haeckel, 1862, Monogr. d. Radiol., p. 445, pl. xxii. figs. 14-16.

Haliomma didymocyrtis, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 816.

Cortical shell thin walled, with spiny surface; pores irregular, roundish, three to nine times as broad as the bars; five to six on the half meridian of each chamber, eight to nine on its half equator. Spines of the surface partly very short, partly as long as the largest pores, either radially or obliquely inserted. Medullary shells both spherical. (Compare the detailed description and figures also of the soft body in my Monograph, loc. cit.)

Dimensions.—Main axis of the cortical shell 0.12, equatorial axis (in the stricture) 0.06; greatest breadth 0.08; pores 0.03 to 0.2, bars 0.002 to 0.006, spines 0.05 to 0.015.

Habitat.—Mediterranean (Messina), Canary Islands (Lanzerote), Haeckel.

Definition.— with double cortical shell and double medullary shell, without polar spines or tubes.

The genus Cypassis differs from Cyphonium by duplication of the cortical twin-shell; from the outer surface of the simple twin-shell arise numerous radial spines, which become connected by anastomosing transverse branches, and in this manner form an outer envelope or mantle. Cypassis may also be regarded as a Cromyodruppa, the double cortical shell of which is constricted in the equatorial plane.

Definition.—Surface of the shell smooth, without thorns or spines.

1. Cypassis palliata, n. sp.

Inner cortical shell thin walled, with regular, circular, hexagonally-framed pores, twice as broad as the bars; seven to eight on the half meridian of each chamber, ten to twelve on its half equator. Outer cortical shell very thin, with smooth surface, and very small, irregular, roundish pores, twice to five times smaller than those of the inner shell. Distance between the two cortical shells equals the diameter of the outer medullary shell, which, like the inner, is spherical. (The network of this species resembles that of Peripanartus amphiconiscus, Pl. 40, fig. 5.)

Dimensions.—Main axis of the external cortical shell 0.18, of the internal 0.12; greatest breadth (in the equator of each chamber) of the former 0.13, of the latter 0.09; pores of the outer 0.002 to 0.005, of the inner shell 0.01, bars 0.002 to 0.005.

Habitat.—South Pacific, Station 288, surface.