Page:Scientific results HMS Challenger vol 18 part 1.djvu/312

104 a deer-horn, one-fourth to one-half as long as the radius of the shell. Some other small spines irregularly scattered over the shell.

Dimensions.—Diameter of the shell 0.12 to 0.16, of the smaller pores 0.001 to 0.004, of the larger armed pores 0.016 to 0.024; length of the spines 0.02 to 0.04.

Habitat.—Central area of the Tropical Pacific, Stations 266 to 272, depth 2425 to 2925 fathoms.

Berlin, p. 59.

Definition.— with simple shells, the pores of which are prolonged into external simple radial tubuli with solid wall; outer mouth of the tubuli truncated, smooth.

The genus Siphonosphæra is, next to Collosphæra, the most common of all Collosphærida, and rich in different species; all agreeing in the tubular prolongation of the pores, and corresponding therefore to Ethmosphæra among the simple Liosphærida.

Definition.—All the pores or apertures of the shell prolonged into tubules.

1. Siphonosphæra pansiphonia, n. sp.

Shell a regular sphere, everywhere occupied by short, regular cylindrical tubes, all of the same size and form. Length of the tubules equal to their breadth and to the intervals between them. Ten to twelve tubules in the half meridian of the shell. This most regular species is nearly allied to Collosphæra regularis, and may be derived from it by tubular prolongation of all the regular pores.

Dimensions.—Diameter of the shell 0.1 to 0.12, length and breadth of the tubules 0.005 to 0.006.

Habitat.—Indian Ocean, Sunda Strait, Rabbe, surface.

2. Siphonosphæra marginata, n. sp.

Shell a regular or subregular sphere, occupied by numerous short cylindrical tubules of different sizes. Six to eight tubules in the half meridian of the shell. Diameter of the tubules about equal to their distance apart, but two to four times as large as their length.

Dimensions.—Diameter of the shell 0.1 to 14; length of the tubules 0.004 to 0.006, breadth of the tubules and the intervals 0.01 to 0.02.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.