Page:Scientific results HMS Challenger vol 18 part 1.djvu/315

Rh half as long as broad, two to four times as broad as the pores and their intervals. This species is nearly related to the foregoing, which it represents in the western tropical part of the Atlantic, but differs constantly in the double size of the shell and the much larger number of the tubules.

Dimensions.—Diameter of the shell 0.06 to 0.09, of the pores 0.002 to 0.004, of the tubules 0.01 to 0.012; their length 0.006 to 0.008, surface.

Habitat.—Tropical and subtropical part of the Western Atlantic, coast of Brazil, &c., Rabbe.

11. Siphonosphæra macrosiphonia, n. sp.

Shell a regular sphere, with numerous very small pores of equal size and distribution. Twelve to sixteen pores in its half meridian. Bars (between the pores) three to four times as broad as their diameter. Only a small number (two to four) of very long cylindrical tubes, irregularly scattered, nearly as long or somewhat longer than the shell diameter; now quite straight, now somewhat curved. Diameter of the cylinders four to six times as large as that of the pores.

Dimensions.—Diameter of the shell 0.1 to 0.12, of the pores 0.002 to 0.004, of the tubules 0.015 to 0.018; length of the tubules 0.08 to 0.16.

Habitat.—Central Tropical Pacific, Station 266 to 272, surface.

12. Siphonosphæra serpula, n. sp. (Pl. 6, fig. 6).

Shell a regular sphere, with numerous very small pores of equal size and distribution. Eight to ten pores in its half meridian; bars between them three to four times as broad as their diameter. Only a small number (six to eight) of very long and snake-like, contorted, cylindrical tubes, irregularly scattered. The shape of the latter is very much like that of the calcareous tubes of some species of Serpula; they are nearly as long as, or longer than, the shell diameter, and four to six times as broad as the pores.

Dimensions.—Diameter of the shell 0.12 to 0.14, of the pores 0.003 to 0.005, of the tubules 0.02 to 0.022; length of the tubules 0.1 to 0.2.

Habitat.—North Eastern Pacific, Station 252 to 262, Sandwich Islands, Haltermann.

13. Siphonosphæra chonophora, n. sp. (Pl. 6, fig. 5).

Shell a regular or subregular sphere, with numerous very small pores of equal size and distribution, ten to twelve in its half meridian. Bars between the pores four to six times their diameter. Only a small number (two to six) of very large funnel-like tubules, irregularly scattered. The inner half of these tubules is a short cylindrical tube, of the same thickness as the shell, three to four times as broad as the pores; the outer half is an irregular funnel, suddenly expanded, with siliceous walls of the utmost tenuity and fragility, often irregularly folded and contorted, like a decayed flower-calyx, often half as large as the shell.

Dimensions.—Diameter of the shell 0.1 to 0.12, of the pores 0.003 to 0.005, inner half of the tubules 0.015 to 0.02, outer funnel-like half 0.05 to 0.08.

Habitat.—South Pacific, Stations 285 to 295, surface.