Page:Scientific results HMS Challenger vol 18 part 1.djvu/719

Rh subregular, circular, two on the breadth of each ring. Radial beams partly piercing. Marginal spines eight to sixteen (commonly twelve), bristle-shaped, very thin, once to three times as long as the diameter of the disk. (On the numerous varieties of this common species compare my Monograph, 1862, p. 498.)

Dimensions.—Diameter of the disk (with ten rings) 0.22; breadth of the inner rings 0.004 to 0.008, of the outer 0.012 to 0.015; pores 0.003 to 0.005.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.

6. Stylodictya solmaris, n. sp.

All rings of the disk concentric, polygonal, with eight to sixteen rounded corners; their breadth increases from the centre; eighth ring twice as broad as the second. Pores subregular circular, large, only one pore on the breadth of each ring. Twenty to thirty marginal spines, bristle-shaped, undulating, about as long as (or longer than) the diameter of the disk.

Dimensions.—Diameter of the disk (with eight rings) 0.2; breadth of the inner rings 0.005, of the outer 0.012; pores 0.004 to 0.008.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

7. Stylodictya octogonia, n. sp.

All rings of the disk concentric, increasing in breadth from the centre. The outer rings (five to eight) regular, octogonal, twice as broad as the circular inner rings. Pores subregular, circular, two to three on the breadth of each ring. Eight piercing perradial spines (alternating with the eight corners of the octogonal rings) bristle-shaped, longer than the diameter of the disk.

Dimensions.—Diameter of the disk (with eight rings) 0.24; breadth of the inner rings 0.006, of the outer 0.014; pores 0.005 to 0.01.

Habitat.—North Atlantic, Station 353, depth 2965 fathoms.

Definition.—Rings of the disk partly concentric, completely annular; partly spiral or interrupted, often irregular.

8. Stylodictya perispira, n. sp.

Inner rings of the disk (two to four) concentric, circular, or roundish, outer rings forming a simple spiral, breadth a little increasing from the centre. Pores subregular, circular, about two on the breadth of each ring. Marginal spines bristle-shaped, ten to fifteen, about as long as the diameter of the disk.

Dimensions.—Diameter of the disk (with eight rings) 0.2; breadth of each ring 0.013; pores 0.004.

Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.