Page:Scientific results HMS Challenger vol 18 part 1.djvu/513

Rh 2. Pipettella tubulosa, n. sp.

Shell ellipsoidal, thin walled, distinctly separated from the two opposite tubes, which are cylindrical, longer than the main axis of the ellipsoid, and one-sixth as broad as the shorter axis. The longer axis of the ellipsoid bears to the shorter the proportion of 5 : 4. Network of the shell and of the tubes equal, regular, with very small circular pores, about as broad as the bars; sixteen to eighteen pores on the half equator of the shell.

Dimensions.—Longer axis of the ellipsoid 0.15, shorter axis 0.12; length of the tubes 0.16 to 0.2, breadth of them 0.02; pores of the network 0.003, bars 0.003.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

3. Pipettella elongata, n. sp.

Shell ellipsoidal, thick walled, distinctly separated from both opposite tubes, which are cylindrical, much prolonged, twice to three times as long as the main axis of the ellipsoid, and one-fifth as broad as the shorter axis. Both axes of the ellipsoid bear the proportion of 3 : 2. Network of the shell and of the tubes irregular with small rounded pores of different size, separated by broader bars (often twice to three times as broad), four to six pores on the half equator of the shell. (This species somewhat recalls Solenosphæra serpentina, Pl. 7, fig. 7; but the tubes are straight, not contorted.)

Dimensions.—Longer axis of the ellipsoid 0.2, shorter axis 0.14; length of the tubes 0.4 to 0.5, breadth 0.03; pores of the network 0.001 to 0.002, bars 0.003 to 0.004.

Habitat.—Central area of the Pacific, Station 271, depth 2425 fathoms.

4. Pipettella prismatica, n. sp. (Pl. 39, fig. 6).

Shell ellipsoidal, thick walled, distinctly marked off from the two opposite tubes, which are longer than its main axis and as broad as one-fifth of it; they are nearly four-sided prismatic, with four strong ribs or edges; these are directed parallel to the main axis, in two meridian planes, perpendicular to one another. The wall of the shell is thickened in the equatorial plane, so as to form a slight stricture on the inside, separating its two halves. Both axes of the ellipsoid bear the proportion of 7 : 6. Network regular, with circular pores, somewhat broader than the bars. The meshes of the shell (fourteen to sixteen on the half equator) are twice as great as those of the tubes, which are arranged in two longitudinal rows between every two ribs (there being eight longitudinal rows on the whole tube). This species is very remarkable for the rudimentary internal equatorial stricture of the shell (transition to the genus Cannartus, Pl. 39, fig. 10), and by the four edges of the tubes, which indicate two of the dimensive axes, the third being represented by the main axis.

Dimensions.—Longer axis of the ellipsoid 0.14, shorter axis 0.12; length of the tubes 0.15 to 0.16, breadth 0.03; pores of the shell 0.008 to 0.01, pores of the tubes 0.004.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.