Page:Scientific results HMS Challenger vol 18 part 2.djvu/536

1412 open terminal mouth of the same breadth. The whole shell is more or less cylindrical, (sometimes conical in the upper part), with two distinct external strictures, or internal annular septa.

Definition.—Pores of the thorax and of the abdomen of nearly equal size and similar form.

1. Tricolocampe cylindrica, n. sp. (Pl. 66, fig. 21).

Shell nearly cylindrical, smooth. Length of the three joints = 2 : 3 : 15, breadth = 3 : 4 : 5. Cephalis hemispherical, with numerous very small pores. Thorax and abdomen cylindrical, of about equal breadth, with equal, circular pores, disposed regularly in transverse rows, three to four rows in the thorax, ten to twelve in the abdomen. Mouth wide open, not constricted.

Dimensions.—Length of the three joints, a 0.02, b 0.03, c 0.15; breadth, a 0.03, b 0.04, c 0.05.

Habitat.—Central Pacific, Stations 265 to 274, depth 2350 to 2925 fathoms.

2. Tricolocampe pupa, Haeckel.

Eucyrtidium pupa, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 293, Taf. vii. fig. 16.

Shell nearly cylindrical, smooth. Length of the three joints = 2 : 2 : 8, breadth = 2 : 3 : 3. Cephalis subspherical, with four larger pores. Thorax and abdomen cylindrical, of about equal breadth, with equal, very small pores, disposed regularly in transverse rows, two rows in the thorax, eight to ten in the abdomen. Mouth wide open, a little constricted.

Dimensions.—Length of the three joints, a 0.02, b 0.02, c 0.08; breadth, a 0.02, b 0.03, c 0.03.

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

3. Tricolocampe polyzona, n. sp. (Pl. 66, fig. 19).

Shell nearly cylindrical, thick-walled. Length of the three joints = 4 : 4 : 12, breadth = 8 : 9 : 9. Cephalis obtuse, conical. Thorax barrel-shaped. Abdomen in the middle part a little constricted. Pores very numerous, subregular, disposed regularly in transverse rows, six to eight in the cephalis, eight to ten in the thorax, twelve to fifteen in the abdomen. Mouth rather constricted, only half as broad as the abdomen.

Dimensions.—Length of the three joints, a 0.04, b 0.04, c 0.12; breadth, a 0.08, b 0.09, c 0.09.

Habitat.—Central Pacific, Stations 266 to 272, depth 2425 to 2925 fathoms; also fossil in the Nicobars and in Barbados.