Page:Scientific results HMS Challenger vol 18 part 2.djvu/433

Rh 14. Dictyocephalus cavea, n. sp.

Shell rough, thin-walled, with slight collar stricture. Length of the two joints = 3 : 10, breadth = 5 : 7. Cephalis hemispherical, thorny, with numerous regular, circular pores. Thorax subcylindrical, with very large, circular, hexagonally-framed pores (in nine longitudinal alternating rows), three to five times as broad as the cephalic pores. Mouth truncate, wide open, without ring-like peristome.

Dimensions.—Cephalis 0.06 long, 0.1 broad; thorax 0.2 long, 0.14 broad.

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

15. Dictyocephalus capito, Ehrenberg.

Dictyocephalus capito, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 289, Taf. vii. fig. 24.

Shell smooth, thin-walled, with sharp collar stricture. Length of the two joints = 7 : 9, breadth = 6 : 8. Cephalis ovate, with numerous irregular, roundish, densely-crowded pores. Thorax ovate, with very few widely-scattered, irregular, roundish pores (broken off in Ehrenberg's figure). Mouth truncate, little constricted, without ring-like peristome.

Dimensions.—Cephalis 0.07 long, 0.06 broad; thorax 0.09 long, 0.08 broad.

Habitat.—Western Tropical Pacific (Philippine Sea) Station 206, depth 2100 fathoms.

16. Dictyocephalus hispidus, Ehrenberg.

Dictyocephalus hispidus, Ehrenberg, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, p. 289, Taf. v. fig. 18.

Shell rough, thin-walled, with deep collar stricture. Length of the two joints = 3 : 4, breadth = 3 : 5. Cephalis subspherical, spiny, with the same irregular, roundish pores as the funnel-shaped or nearly ovate thorax. Mouth truncate, little narrower than the thorax, without ring-like peristome.

Dimensions.—Cephalis 0.03 long, 0.03 broad; thorax 0.04 long, 0.05 broad.

Habitat.—Tropical Atlantic, Mexican Gulf (Ehrenberg); Station 338, depth 1990 fathoms.

Definition.— with the basal mouth of the shell fenestrated (vel Dicyrtida eradiata clausa).