Page:Scientific results HMS Challenger vol 18 part 2.djvu/688

1564 from this by eight short teeth, four centripetal on the larger lower ring and four perradial centrifugal on the smaller upper ring.

Dimensions.—Diameter of the basal ring 0.03, of the apical ring 0.015.

Habitat.—Fossil in Tertiary rocks of Sicily, Caltanisetta (Ehrenberg); living in the Central Pacific, Station 270 to 272, surface.

3. Distephanus stauracanthus, Haeckel.

Dictyocha stauracanthus, Ehrenberg, 1845, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 76; Mikrogeol., 1854, Taf. xxxiii., Nr. xv. fig. 10.

Each pileated piece of the skeleton exhibits four lateral meshes around the central mesh, and is composed of two horizontal rings, which are connected by four perradial beams arising from the corners of the upper and smaller square ring. Lower ring octagonal, with eight peripheral adradial spines, and with four interradial centripetal teeth on the inside.

Dimensions.—Diameter of the basal ring 0.03, of the apical ring 0.004.

Habitat.—Fossil in Tertiary rocks of North America (Hollis Cliff, Virginia; Norwich, Connecticut).

4. Distephanus asteroides, n. sp.

Dictyocha asteroides, Haeckel, 1881, Prodromus.

Each pileated piece of the skeleton exhibits five lateral meshes around the central mesh (or the upper ring). Five peripheral spines (on the corners of the lower ring) simple, not articulated.

Dimensions.—Diameter of the basal ring 0.02, of the apical ring, 0.007.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

5. Distephanus pentasterias, Haeckel.

Dictyocha pentasterias, Ehrenberg, 1839, Mikrogeol., Taf. xviii. fig. 61.

? Dictyocha quinaria, Ehrenberg, 1842, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 265.

? Dictyocha elegans, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 80; Mikrogeol., 1854, Taf. xxii. fig. 51.

Actiniscus elegans, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 51.

Each pileated piece of the skeleton exhibits five lateral meshes around the central mesh (or the upper ring). Five peripheral spines (on the corners of the lower ring) articulated, triangular, with three distinct joints (tapering towards the distal end).

Dimensions.—Diameter of the basal ring 0.012 to 0.018, of the apical ring 0.002 to 0.003.

Habitat.—Cosmopolitan; living in the depths of the Atlantic and Central Pacific, Stations 247, 270 to 272, depths 2530 and 2600 to 2925 fathoms; fossil in Tertiary deposits (Tripel of Caltanisetta, Sicily; Richmond, Virginia).