Page:Scientific results HMS Challenger vol 18 part 2.djvu/745

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Definition.— with triangular meshes in the network, the tangential tubes of which form a simple smooth lattice-sphere. No radial tubes at the nodal points.

The genus Aularia is the simplest form of the subfamily Aularida, or of those Aulosphærida in which the network of the shell is composed of regular or subregular triangular meshes; they are the main group of the family, much more common and far richer in distinct forms than the Aulonida (or the Aulosphærida with polygonal meshes). The shell of Aularia, the probable ancestral form of the family, is a simple lattice-sphere with smooth surface, and differs from the common Aulosphæra in the absence of radial tubes, arising at the nodal points.

1. Aularia ternaria, n. sp. (Pl. 111, fig. 2).

Tangential tubes of the network cylindrical, straight, smooth, of equal breadth. Triangular meshes of the reticular sphere very regular, equilateral triangular. This species is the simplest of all Aulosphærida and similar to the common Aulosphæra trigonopa, but has no radial tubes.

Dimensions.—Diameter of the sphere 1.0 to 2.0; tubes 0.1 to 0.15 long, 0.007 to 0.01 broad.

Habitat.—Central Pacific, Stations 270 to 274, surface.

2. Aularia tubularia, n. sp.

Tangential tubes of the network cylindrical, straight, of equal breadth, thorny, covered with numerous short bristle-shaped thorns, which are all of the same length and perpendicular to the tube.

Dimensions.—Diameter of the sphere 3.0; tubes 0.15 long, 0.005 broad.

Habitat.—South Pacific, Station 291, depth 2250 fathoms.

3. Aularia trigonaria, n. sp.

Tangential tubes of the network smooth, very thin in the middle part, gradually dilated towards both ends, so that the nodal points of the network are inflated. (Similar to Aulosphæra sceptrophora, Pl. 109, fig. 3, but without radial tubes.)

Dimensions.—Diameter of the sphere 2.2; tubes 0.1 long, 0.002 broad in the middle part, 0.01 on both sides.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.