Page:Scientific results HMS Challenger vol 18 part 2.djvu/568

1444 The genus Stichocampe, together with the three following genera, represent a peculiar small group among the Stichocyrtida, differing from all other members of this family in the possession of three free terminal feet around the open mouth. In the two genera, Stichocampe and Stichopterium, these three feet are the terminal prolongations of three lateral ribs or crests, while in the two genera developed later, Podocampe and Stichopodium, the three original ribs are lost, and only the three free feet remain. Stichocampe (the most primitive of these four genera) may be derived from Theopodium by addition of new joints.

1. Stichocampe divergens, n. sp.

Shell spiny, broadly pyramidal, with six deep strictures. Seven joints gradually increasing in breadth and length, the seventh twice as broad as the fourth. Pores subregular, circular, hexagonally framed. The prominent edges of the pyramis are prolonged over the wide mouth into three slender, straight, divergent feet, half as long as the shell.

Dimensions.—Length of the shell (with seven joints) 0.3, of the last joint 0.06, of the fourth 0.03; breadth 0.25.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

2. Stichocampe convergens, n. sp.

Shell smooth, slenderly pyramidal, with eight distinct strictures. All nine joints nearly equal in length. Pores regular, circular, forming three or four transverse rows in each joint. The smooth edges of the pyramis are prolonged over the wide mouth into three slender, slightly curved, and convergent feet, twice as long as one joint.

Dimensions.—Length of the shell (with nine joints) 0.25, of each joint, about 0.035; breadth 0.11.

Habitat.—Central Pacific, Station 273, depth 2350 fathoms.

Definition.— (vel Stichocyrtida triradiata aperta), with three lateral ribs or wings, which are prolonged into three latticed, terminal feet. Cephalis with a horn.

The genus Stichopterium has in general the same shell-formation as the nearly allied Stichocampe, but differs from this ancestral form in the fenestration of the three terminal feet. It corresponds, therefore, to Pterocanium among the Tricyrtida.