Page:Scientific results HMS Challenger vol 18 part 2.djvu/88

964 on the outer and upper thorny. Apical horn and the three divergent feet nearly equal, straight, about as long as the sagittal ring, with three thorny edges.

Dimensions.—Height of the sagittal ring 0.1 to 0.12, breadth 0.07 to 0.09.

Habitat.—Central Pacific, Stations 270 to 274, depth 2350 to 2925 fathoms.

2. Cortiniscus dipylaris, n. sp. (Pl. 92, fig. 13).

Sagittal ring nearly semicircular, with prominent distorted edges and six pairs of small roundish papillate tubercles (three pairs on the straight dorsal, three on the curved ventral rod). Apical horn short and stout, with a tuberculate knob. Basal ring smaller than the sagittal ring with two elliptical gates. Three feet short and stout, irregularly branched like a cauliflower, with numerous short papillate tubercles.

Dimensions.—Height of the sagittal ring 0.11, breadth 0.08.

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

3. Cortiniscus tripylaris, n. sp.

Sagittal ring elliptical, smooth. Apical horn conical, smooth. Basal ring larger than the sagittal ring, with three elliptical gates of equal size; two paired, posterior (jugular pores) between the basal parts of the caudal foot and the two pectoral feet, and an odd, anterior (sternal pore) between the basal parts of the two pectoral feet and a connecting horizontal convex sternal bow.

Dimensions.—Height of the sagittal ring 0.09, breadth 0.06.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

4. Cortiniscus tetrapylaris, n. sp.

Sagittal ring elliptical, with four pairs of short branched thorns, two posterior on the straight dorsal, and two anterior on the curved ventral rod. Basal ring smaller than the sagittal ring, with four triangular gates; the two anterior (jugular pores) a little smaller than the two posterior (cardinal pores). Apical horn and the three divergent feet shorter than the sagittal ring, irregularly branched, with curved, often tuberculate branches.

Dimensions.—Height of the sagittal ring 0.08 to 0.12, breadth 0.06 to 0.1.

Habitat.—Fossil in Barbados.

5. Cortiniscus typicus, n. sp. (Pl. 92, fig. 12).

Sagittal ring ovate, thorny, with three distorted edges; dorsal rod nearly straight and vertical prolonged upwards into a stout thorny apical horn, downwards into the caudal foot. Basal ring smaller than the sagittal ring, with four elliptical or nearly triangular gates; the two anterior (jugular pores) about half as large as the two posterior (cardinal pores). Three feet of equal size, thorny, divergent, straight or slightly curved, about as long as the diameter of the sagittal ring.

Dimensions.—Height of the sagittal ring 0.14 to 0.18, breadth 0.1 to 0.12.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, at various depths.