Page:Scientific results HMS Challenger vol 18 part 2.djvu/677

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Definition.— with a skeleton composed of numerous cap-shaped pieces, which lie tangentially scattered on the surface of the spherical calymma. Each piece is a hemispherical or flatly cap-shaped siliceous body, often with radial striations, and with a thin solid wall.

Definition.— with a skeleton composed of solid, cap-shaped or hemispherical, not fenestrated, pieces.

The genus Catinulus differs from all the other Cannorrhaphida in the peculiar shape of the numerous siliceous pieces, which are scattered on the surface of the calymma and compose their rudimentary skeleton. These pieces are neither hollow rings (as in the Dictyochida), nor hollow tubes (as in the Cannobelida), but solid hemispherical caps or more flatly vaulted small dishes. All the complete specimens of this genus which I observed exhibited four equal central capsules in the spherical calymma.

1. Catinulus quadrifidus, n. sp. (Pl. 117, figs. 8, 8a).

Cap-shaped pieces of the skeleton flatly vaulted, three times as broad as high, smooth; the marginal ring with fine radial ribs and with smooth margin.

Dimensions.—Diameter of the calymma 0.6 to 0.8, of the four central capsules 0.12 to 0.2; breadth of the concave caps 0.024, height 0.008.

Habitat.—South Atlantic, Station 323, depth 1900 fathoms.

2. Catinulus catillum, n. sp.

Cap-shaped pieces of the skeleton flatly vaulted, three times as broad as high, rough, covered with numerous small spinules; the marginal ring with stout radial ribs and a corona of denticles on the margin.

Dimensions.—Breadth of the concave caps 0.03, height 0.01.

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

3. Catinulus lopadium, n. sp.

Cap-shaped pieces of the skeleton hemispherical, twice as broad as high, smooth; the marginal ring smooth, slightly radiate, with thickened smooth margin.

Dimensions.—Diameter of the calymma 1.2, of the central capsule 0.22; breadth of the concave caps 0.024, height 0.012.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.