Page:Scientific results HMS Challenger vol 18 part 2.djvu/872

latter (with the terminal coronets), and the anchor pencils, covering the surface of the thicket and the mantle, seem to project over the surface of the calymma. The entire form of the latter is therefore a symmetrical polyhedron. The phæodium fills up a small part only of the calymma, and is usually enclosed in the two galeæ and their rhinocannæ (Pl. 127, figs. 5, 9), but often also a part of the phæodium is scattered around the oral half of the central capsule.

Synopsis of the Genera of Cœlographida.

I. Subfamily Cœlotholida. Rhinocanna of each valve with two paired lateral frenula. The distal ends of the dichotomous brushes are not united by anastomoses, and form an outer bivalved fork-thicket.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Eight paired styles (four on each valve),			731. Cœlotholus.
		Twelve paired styles (six on each valve),			732. Cœlothauma.
		Sixteen paired styles (eight on each valve),			733. Cœlothamnus.
II. Subfamily Cœloplegmida. Rhinocanna of each valve with an odd sagittal frenulum. The distal ends of the dichotomous brushes are united by anastomoses, and form an outer bivalved lattice-mantle.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Mantle with six styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	One odd and two paired styles on each valve,	734. Cœlographis.
		Mantle with eight styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Two odd and two paired styles on each valve,	735. Cœlospathis.
		Mantle with ten styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	One odd and four paired styles on each valve,	736. Cœlodecas.
		Mantle with twelve styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Two odd and four paired styles on each valve,	737. Cœlostylus.
		Mantle with fourteen styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	One odd and six paired styles on each valve,	738. Cœloplegma.
		Mantle with sixteen styles.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Two odd and six paired styles on each valve,	739. Cœlagalma.

Subfamily 1. Cœlotholida, Haeckel.

Definition.—Cœlographida with two paired lateral frenula on each galea, and with free terminal branches on the hollow radial tubes, without an external lattice-mantle. Eight to sixteen long styles are prominent over the surface of the fork-thicket, which is composed of the caudal brush and the dichotomous basal branches of the styles.

Genus 731. Cœlotholus,^[1] n. gen.

Definition.—Cœlographida with two paired lateral frenula on each galea, without external lattice-mantle, armed with eight styles (two pairs of styles on each valve).

1. Cœlotholus = Hollow cupola; κοίλος, θόλος.