Page:Scientific results HMS Challenger vol 18 part 2.djvu/560

Synopsis of the Genera of Podocampida.

I. Subfamily Stichopilida. Mouth of the terminal joint a simple wide opening.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Three lateral appendices or wings (no terminal feet).	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Lateral wings are solid spines.		Cephalis with horn,	626. Stichopilium.
				Lateral wings are latticed.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	With horn,	627. Artopilium.
						Without horn,	628. Pteropilium.
		Three terminal appendices or feet at the peristome (all with cephalic horn).	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Three lateral ribs or crests prolonged into the three terminal feet.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Feet solid,	629. Stichocampe.
						Feet latticed,	630. Stichopterium.
				No lateral ribs. Three terminal feet free.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Feet solid,	631. Podocampe.
						Feet latticed,	632. Stichopodium.
II. Subfamily Stichoperida. Mouth of the terminal joint closed by a lattice-plate.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Last joint rounded, without a vertical basal spine (cephalis with horn).	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	Three lateral solid ribs (or rows of spines),			633. Stichopera.
				Three lateral latticed wings (or rows of wings),			634. Cyrtopera.
		Last joint conical, pointed, with a vertical basal spine.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Three lateral solid ribs (cephalis with an apical horn),			635. Artopera.

Subfamily 1. Stichopilida, Haeckel, 1881, Prodromus, p. 439.

Definition.—Podocampida with the terminal mouth of the shell open (vel Stichocyrtida triradiata aperta).

Genus 626. Stichopilium,^[1] Haeckel, 1881, Prodromus, p. 439.

Definition.—Stichopilida (vel Stichocyrtida triradiata aperta) with three solid lateral ribs or wings, without terminal feet. Cephalis with a horn.

The genus Stichopilium is the most primitive among all Stichocyrtida, and represents perhaps the common ancestral form of this family. The shell is composed of four or more joints (sometimes ten to twelve), has a wide open terminal mouth, and three lateral solid wings or ribs (sometimes a little latticed on the base). Stichopilium may be derived from Theopilium or Pterocorys by addition of new terminal joints.

Subgenus 1. Triacartus, Haeckel, 1881, Prodromus, p. 437.

Definition.—Shell with three annular strictures, and four distinct joints.

1. Stichopilium = Hat with a row of joints; στίχος, πίλιον.