Page:Scientific results HMS Challenger vol 18 part 2.djvu/569

Rh 1. Stichopterium pterocanium, n. sp.

Shell campanulate, with three distinct strictures. Length of the four joints = 2 : 3 : 4 : 3. Cephalis subspherical, with a conical horn of twice the length. Pores regular, hexagonal, with thin bars. From the collar stricture arise three divergent ribs, which in the fourth joint become latticed and prolonged over its mouth into three slender, pyramidal, latticed, divergent feet, nearly as long as the shell. (Similar to Pterocanium bicorne, Pl. 73, fig. 5, but with four distinct strictures.)

Dimensions.—Length of the shell (with four joints) 0.12, breadth 0.1. Length of the single joints, a 0.02, b 0.03, c 0.04, d 0.03.

Habitat.—South Pacific (off Patagonia), Station 304, surface.

2. Stichopterium virgineum, n. sp.

Shell three-sided, pyramidal, with four sharp strictures. Length of the five joints = 1 : 4 : 3 : 2 : 1. Cephalis hemispherical, with a pyramidal horn three times the length. Pores subregular, circular, in the second campanulate joint twice or three times as broad as in the four other joints. From the base of the cephalic horn arise three divergent ribs, which descend over the whole shell, and in the fourth joint become latticed and prolonged over the wide mouth of the fifth joint into three latticed, pyramidal feet, as long as the second joint. (Similar in general form to Pterocanium virgineum, Pl. 73, fig. 6.)

Dimensions.—Length of the shell (with five joints) 0.22, breadth 0.16. Length of the single joints, a 0.02, b 0.08, c 0.06, d 0.04, e 0.02.

Habitat.—Central Pacific, Station 281, surface.

3. Stichopterium dictyopodium, n. sp.

Shell subovate, with five internal annular septa. The third and the fourth joints are about twice as long as the two first and the two last joints. The fifth joint is the broadest. Pores small and numerous, regular, circular. The three first joints are without ribs. From the third stricture arise three divergent, triangular, latticed wings, which descend along the three last joints, and are prolonged over the wide mouth as three slender, fenestrated, divergent feet, two-thirds as long as the shell.

Dimensions.—Length of the shell (with six joints) 0.18, breadth 0.12. Length of the two middle joints 0.04, of the four others 0.02 to 0.03.

Habitat.—South Pacific, Station 288, surface.

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