Page:Scientific results HMS Challenger vol 18 part 2.djvu/343

Rh 1. Clathromitra pterophormis, n. sp. (Pl. 57, fig. 8).

Cephalis very large, hemispherical, about as long and half as broad as the three-sided pyramidal thorax; both with irregular, polygonal meshes. Apical horn three to four times as long as the frontal horn and the three basal feet. All five spines three-sided prismatic, with nearly smooth edges. Three lateral wings half as broad as the cephalis.

Dimensions.—Cephalis 0.05 long, 0.1 broad; thorax 0.05 long, 0.15 broad.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

2. Clathromitra pentacantha, n. sp.

Cephalis large, hemispherical, half as long as the three-sided pyramidal thorax; both with irregular, roundish meshes. Apical horn of about the same length as the frontal horn, and twice as long as the three basal feet. All five spines three-sided prismatic, with denticulated edges. Three lateral wings about as broad as the cephalis.

Dimensions.—Cephalis 0.04 long, 0.08 broad; thorax 0.1 long, 0.2 broad.

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

Definition.— (vel Dicyrtida triradiata aperta) with three prominent lateral ribs on the thorax, alternating with three large holes (or thoracic gates). The three ribs are connected with the central apical horn of the cephalis by three vertical latticed wings.

The genus Clathrocorys differs from the two preceding nearly allied genera in the incomplete fenestration of the thorax, the three perradial ribs of which are separated by three large interradial holes. It has therefore the same relation to Callimitra that Clathrocanium bears to Dictyophimus.

1. Clathrocorys murrayi, n. sp. (Pl. 64, fig. 8).

Cephalis pear-shaped, with irregularly square pores. From the centre of its base there arise four strong, prismatic, radial beams of nearly equal size, the vertical, straight, cephalic horn being little longer than the three divergent, somewhat curved feet. In the three meridional planes (between the horn and each foot) a few rather thick branches arise, which by communication of the ramules form the three vertical latticed wings; each wing with two large meshes, three to five meshes of medium size, and three to four parallel arachnoidal rows of small, square, distal meshes. The three walls of the flat pyramidal thorax (between every two feet) are formed in the upper part by squarish network