Page:Scientific results HMS Challenger vol 18 part 2.djvu/811

Rh 3. Castanissa richardsi, n. sp.

Pores subregular, circular, about as broad as the bars. Bristles twice as long as one pore. Radial main-spines (about twenty) slender, cylindrical, irregularly curved, with dimpled surface (like those in Pl. 113, fig. 5a). Mouth with a corona of six stout, parallel, triangular teeth.

Dimensions.—Diameter of the shell 0.3 to 0.35, of the pores 0.015.

Habitat.—North Atlantic, Station 354, surface.

4. Castanissa crosbiei, n. sp.

Pores irregular, roundish, two to three times as broad as the bars. Bristles one-third as long as the radius. Radial main-spines very numerous, straight, cylindrical, smooth, about as long as the diameter of the shell. Mouth with ten or twelve irregular, conical, parallel teeth.

Dimensions.—Diameter of the shell 0.28, of the pores 0.01 to 0.015.

Habitat.—North Pacific, Stations 231 to 235, surface.

5. Castanissa macleani, n. sp.

Pores irregular, roundish or polygonal, two to four times as broad as the bars. Bristles about one-fourth as long as the radius. Radial main-spines numerous, straight, conical, stout, with dimpled surface, shorter than the radius. Mouth with six to eight irregular conical teeth.

Dimensions.—Diameter of the shell 0.32, of the pores 0.012 to 0.024.

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

6. Castanissa hoylei, n. sp.

Pores irregular, polygonal, two to three times as broad as the bars. Bristles nearly half as long as the radius. Radial main-spines (about thirty) very long and thin, cylindrical, irregularly curved, at the conical base inflated and fenestrated; shell therefore slightly polyhedral. Mouth with five strong conical teeth.

Dimensions.—Diameter of the shell 0.35 to 0.4, of the pores 0.02 to 0.03.

Habitat.—North Pacific, Station 245 to 250, surface.

Definition.— with branched radial main-spines and a simple smooth mouth.

The genus Castanopsis differs from its ancestral form Castanidium in the ramification of the radial main-spines; the branches are usually very irregular and often partly