Page:Scientific results HMS Challenger vol 18 part 2.djvu/104

980

Definition.— with six large gates (four lateral and two basal). Skeleton composed of two complete rings (the sagittal and basal) and one incomplete (frontal) ring. Basal ring provided with typical, regularly disposed, descending feet (cortinar feet).

The genus Podocoronis differs from the two preceding nearly allied genera in the development of typical radial feet on the basal ring, which by their regular disposition and their general appearance among the and  obtain great morphological importance. According to the different number and disposition of these basal feet (or "cortinar feet"), the following subgenera may be distinguished (regarded in my Prodromus, 1881, p. 445, as separate genera):—Dipocoronis with two lateral feet, Tripocoronis with three cortinar feet (most important!), Tetracoronis with four crossed feet, Hexacoronis with six radial feet, Stylocoronis with numerous (8 or more feet). These subgenera have important relations to the corresponding genera of Zygospyrida.

Definition.—Basal ring with two descending lateral feet (right and left) as prolongations of the frontal ring.

1. Podocoronis dipodiscus, n. sp.

Basal ring nearly circular, with two conical, straight, parallel descending feet, which are direct lateral prolongations of the subcircular frontal ring, and half as long as it. The ovate sagittal ring bears at the apex a short conical vertical horn. All rings nearly smooth.

Dimensions.—Height of the frontal ring 0.12, breadth 0.14.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

2. Podocoronis toxarium, n. sp. (Pl. 83, fig. 7).

Basal ring elliptical, with two descending, slightly curved conical feet, lateral prolongations of the subcircular frontal ring. The ovate sagittal ring bears at the apex a cylindrical vertical horn, which is connected by two descending lateral arches (or galear arches) with the uppermost part of the frontal ring.

Dimensions.—Height of the frontal ring 0.1, breadth 0.13.

Habitat.—Central Pacific, Stations 265 to 268, depth 2900 fathoms.