Page:Scientific results HMS Challenger vol 18 part 2.djvu/729

as in the closely allied Aulosphærida (Pl. 111, fig. 3). The pseudopodia arising from the central capsule form a loose network in the calymma, and proceed over its surface as numerous delicate radial filaments, often supported by the radial spines.

Synopsis of the Genera of Sagosphærida.

I. Subfamily Sagenida. Wall of the spherical shell composed of a simple lattice-plate with or without pyramidal elevations.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Surface of the spherical shell smooth or spiny, without pyramidal elevations.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	No radial spines, surface smooth,	675. Sagena.
				Radial spines in the nodal points,	676. Sagosphæra.
		Surface of the spherical shell covered with pyramidal or tent-shaped elevations.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Pyramids without internal axial rod,	677. Sagoscena.
				Pyramids with an internal radial axial rod,	678. Sagenoscena.
II. Subfamily Sagmarida. Wall of the spherical shell spongy, composed of an irregular complicated wicker-work.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Surface of the spherical shell smooth or spiny, without pyramidal elevations.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Surface smooth, without radial spines,	679. Sagmarium.
				Surface studded with radial spines,	680. Sagmidium.
		Surface of the spherical shell covered with pyramidal elevations.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	Pyramids on the top with a radial spine or a bunch of divergent spines,	681. Sagoplegma.

Subfamily 1. Sagenida, Haeckel.

Definition.—Sagosphærida with a delicate spherical shell, the thin wall of which is composed of a simple lattice-plate, not spongy.

Genus 675. Sagena,^[1] n. gen.

Definition..—Sagosphærida with a delicate shell, the thin wall of which is composed of a simple smooth lattice-plate, without radial spines.

The genus Sagena is the simplest of the Sagosphærida and may be regarded as the common ancestral form of this family. The delicate wall of the simple spherical lattice-shell is composed of large, regular, or subregular, triangular meshes, the nodal points of which bear no radial spines. It agrees therefore perfectly with Aularia, and differs from this simplest form of Aulosphærida only in the structure of the skeleton, which is composed not of hollow articulated tubes, but of very thin solid threads. The skeleton may therefore also be confounded with Cenosphæra, but the central capsule of this latter is "peripylean," with numerous fine pores in the entire wall, whilst that of Sagena is "tripylean," having the proboscis of all Phæodaria.

1. Sagena = Drag-net; σαγήνη.