Page:Scientific results HMS Challenger vol 18 part 2.djvu/857

pole of the main axis, whilst the two lateral accessory openings, or parapylæ, lie on both sides of the posterior (or aboral) pole, to the right and left. The position of the capsule is therefore the same as in the preceding Concharida (Pls. 123-125), and the following Cœlographida (Pls. 126-128). The large nucleus, enclosed in the central capsule, is usually half as broad, and contains numerous nucleoli.

The calymma, or the extracapsular jelly-veil, is in the Cœlodendrida usually spherical, very voluminous, and includes the entire skeleton, the thicket of the Cœlodorida as well as the lattice-mantle of the Cœlodrymida. Only the outermost terminal branches of the tubes in the former, and the radial bristles and spathillæ on the surface of the latter, remain free and project beyond the surface of the calymma. The phæodium is usually very large, three to four times as broad as the central capsule, and envelops it often completely. Usually it envelops only the anterior half of it, and the proboscis (Pl. 121, figs. 1, 9). Often numerous green, brown, or blackish phæodellæ are scattered through the whole calymma, and sometimes accumulate in a superficial layer on its surface. The galea of both valves is usually also filled up by the phæodium.

Synopsis of the Genera of Cœlodendrida.

I. Subfamily Cœlodorida. Hollow tubes, arising from the galea of both valves, simple or dichotomously branched; the branches always free, not anastomosing. No outer lattice-mantle.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Tubes simple, not branched,	727. Cœlodoras.
		Tubes forked or dichotomously branched,	728. Cœlodendrum.
II. Subfamily Cœlodrymida. Hollow tubes, arising from the galea of both valves, dichotomously branched; the branches anastomose and form an outer bivalved lattice-mantle.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Lattice-mantle simple; its meshes lying in a spherical surface,	729. Cœlodrymus.
		Lattice-mantle spongy; its meshes lying in different planes,	730. Cœlodasea.

Subfamily I. Cœlodorida, Haeckel.

Definition.—Cœlodendrida without an external bivalved lattice-mantle, with simple or branched hollow tubes, the terminal branches of which are free, not anastomosing.

Genus 727. Cœlodoras,^[1] n. gen.

Definition.—Cœlodendrida without external lattice-mantle, with simple, not branched, radial tubes, which arise separately from the galea.

1. Cœlodoras = Hollow spear; κοίλος, δόρας.