Page:Scientific results HMS Challenger vol 18 part 1.djvu/1007

Rh 1. Astrocapsa tritonis, n. sp.

Aspinal holes circular, with smooth convex margin and four circular aspinal pores. Porules of the shell simple, without ring and dimple. Four edges of the spines smooth, their outer free part about as long as the diameter of the shell.

Dimensions.—Diameter of the shell 0.25; outer length of the spines 0.3.

Habitat.—North Atlantic, Færöe Channel, Gulf Stream (expedition of H.M.S "Triton," August, 1882), John Murray, surface.

2. Astrocapsa stellata, n. sp. (Pl. 133, fig. 10).

Aspinal holes cruciform, with high crenated margin. Four aspinal pores of each hole egg-shaped. Porules of the shell simple, without ring and dimple. Four edges of the spines denticulate; their outer free part twice to three times as long as the diameter of the shell.

Dimensions.—Diameter of the shell 0.36; outer length of the spines 0.5 to 0.8.

Habitat.—Antarctic Ocean (near Kerguelen), Station 152, surface.

3. Astrocapsa quadrifida, n. sp.

Aspinal holes four-lobed, with four prominent teeth between the four roundish aspinal pores. Porules of the shell surrounded by a high polygonal smooth ring. Four edges of the spines denticulate; their outer free part about as long as the radius of the shell.

Dimensions.—Diameter of the shell 0.28; outer length of the spines 0.15.

Habitat.—North Pacific, Station 241, surface.

4. Astrocapsa coronata, n. sp. (Pl. 133, fig. 9).

Aspinal holes circular, with a coronet of numerous thin parallel teeth. Porules of the shell in dimples on irregular polygonal small plates, with coronated ring. Four edges of the spines denticulate; their outer free part about twice as long as the diameter of the shell.

Dimensions.—Diameter of the shell 0.4 to 0.5 ; outer length of the spines 1.0 to 1.2.

Habitat.—North Atlantic, Færöe Channel, Gulf Stream (expedition of the "Knight Errant," 1880), John Murray, surface and at depths varying from 10 to 200 fathoms.

Definition.—Radial spines not connected with the porous shell, shorter than its radius; therefore the shell pierced by twenty perspinal pores (each one in the ideal radial prolongation of one spine).