Page:Scientific results HMS Challenger vol 18 part 2.djvu/534

1410 4. Theosyringium tubulus, Haeckel.

Eucyrtidium tubulus, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, Taf. xi. fig. 6.

Shell smooth, slenderly spindle-shaped, with two slight strictures. Length of the three joints = 2 : 10 : 8, breadth = 3 : 6 : 3. Cephalis hemispherical, hyaline, with a stout, pyramidal horn of the same length. Thorax spindle-shaped. Abdomen inversely conical, half as long as the thorax prolonged into a slender, cylindrical tube. Pores subregular, circular.

Dimensions.—Length of the three joints, a 0.02, b 0.1, c 0.08; breadth, a 0.03, b 0.06, c 0.03.

Habitat.—Fossil in Barbados.

Definition.— (vel Tricyrtida eradiata aperta) with cylindrical abdomen, and wide open truncate mouth. Cephalis with two horns, or a bunch of horns.

The genus Lophocyrtis differs from its ancestral form Theocyrtis only in the armature of the cephalis, bearing instead of a single horn either two divergent horns, or a bunch, or coronal of numerous spines. The slender abdomen is in both genera cylindrical, with wide open mouth.

1. Lophocyrtis holothuria, n. sp.

Shell smooth, slender, with two distinct strictures. Length of the three joints = 1 : 2 : 4, breadth = 2 : 4 : 3. Cephalis hemispherical, with a bunch of five divergent, conical horns, the middle of which is larger and vertical, nearly as long as the thorax. Thorax campanulate, half as long as the cylindrical abdomen. Mouth truncate. Pores regular, circular, quincuncial. (Similar to Theocyrtis cylindrica, but with different cephalis and thorax.)

Dimensions.—Length of the three joints, a 0.03, b 0.05, c 0.1; breadth, a 0.04, b 0.07, c 0.06.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

2. Lophocyrtis stephanophora, Haeckel.

Eucyrtidium stephanophorum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin p. 72, Taf. viii. fig. 14.

Shell smooth, slender, with deep collar and indistinct lumbar stricture. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 3. Cephalis subspherical, with very small circular pores, and a corona of three to nine short conical spines. Thorax campanulate, with regular, circular pores, which are half or one-third as broad as those of the cylindrical abdomen.

Dimensions.—Length of the three joints, a 0.025, b 0.05, c 0.09; breadth, a 0.025, b 0.06, c 0.06.

Habitat.—Fossil in Barbados.