Page:Scientific results HMS Challenger vol 18 part 2.djvu/592

Synopsis of the Genera of Lithocampida.

I. Subfamily Stichocorida. Terminal mouth of the last shell-joint a simple wide opening.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	All annular septa or transverse strictures of the shell separated, parallel, not connected by a spiral line.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Shell conical or cylindrical. Mouth of the last joint wide open, not distinctly constricted.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \\\ \\\ \\\ \ \end{matrix}}\right.}$	Conical, gradually dilated.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	With horn,	642. Lithostrobus.
								No horn,	643. Dictyomitra.
						Conical above, cylindrical below.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	With horn,	644. Stichocorys.
						Cylindrical or subcylindrical.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	With horn,	645. Artostrobus.
								No horn,	646. Lithomitra.
				Shell ovate or spindle-shaped. Mouth of the last joint constricted.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Cephalis with a horn.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Last joint not tubular,	647. Eucyrtidium.
								Last joint a long tube,	648. Eusyringium.
						Cephalis without horn.	$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Cephalis with tube.	649. Siphocampe.
								Cephalis without tube,	650. Lithocampe.
		Annular septa or transverse strictures of the shell all or partly obliquely descending and connected spirally.					$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	With horn,	651. Spirocyrtis.
								No horn,	652. Spirocampe.
II. Subfamily Stichocapsida. Terminal mouth closed by a lattice-plate.	$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Last joint rounded, without a vertical basal spine.					$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \ \end{matrix}}\right.}$	With horn,	653. Cyrtocapsa.
								No horn,	654. Stichocapsa.
		Last joint conical, pointed, with a vertical, basal spine.					$\scriptstyle {\left\{{\begin{matrix}\ \\\ \end{matrix}}\right.}$	Cephalis with horn,	655. Artocapsa.

Subfamily 1. Stichocorida, Haeckel, 1881, Prodromus, p. 438.

Definition.—Lithocampida with the terminal mouth of the shell open (vel Stichocyrtida eradiata aperta).

Genus 642. Lithostrobus,^[1] Bütschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 529.

Definition.—Stichocorida (vel Stichocyrtida eradiata aperta), with conical shell, gradually dilated towards the wide open mouth. Cephalis with a horn.

The genus Lithostrobus is probably the most primitive among the Lithocampida, and comprises those forms of this family in which the slender, conical shell is gradually dilated towards the wide, terminal mouth, each joint being broader than the preceding.

1. Lithostrobus = Cone of silex; λίθος, στρόβος.