Page:Scientific results HMS Challenger vol 18 part 2.djvu/620

1496 mouth. Cephalis with a stout pyramidal horn of the same length. Whole surface spiny. Pores irregular, roundish.

Dimensions.—Length of the shell (with six joints) 0.22. Length of the single joints, a 0.02, b 0.06, c 0.04, d 0.02, e 0.02, f 0.06; breadth (in the third joint) 0.11.

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

Definition.— (vel Stichocyrtida eradiata aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, and prolonged into a terminal cylindrical tube. Cephalis with a solid horn.

The genus Eusyringium differs from the preceding closely allied genus Eucyrtidium in the peculiar formation of the last shell-joint, representing a narrow, cylindrical, fenestrated tube. It exhibits, therefore, to the latter the same relation as Theosyringium bears to Theocorys.

Definition.—Shell with three strictures and four joints; the third joint is the largest, inflated, and much broader than the three others.

1. Eusyringium conosiphon, n. sp. (Pl. 78, fig. 10).

Shell with four joints, very thick-walled, rough. Cephalis hemispherical, with a very stout, smooth, three-sided pyramidal horn of the same length and breadth. Thorax hemispherical. Third joint subspherical, three times as long, and twice as broad as the thorax, and of the same length as the slender, inversely conical fourth joint. Pores in the three first joints subregular, circular, in the fourth joint irregular.

Dimensions.—Length of the shell (with four joints) 0.25. Length of the single joint a 0.02, b 0.03, c 0.1, d 0.1; breadth 0.12.

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

2. Eusyringium pachysiphon, n. sp. (Pl. 78, fig. 11).

Shell with four joints, very thick-walled, rough. Cephalis conical, with a thick, dimpled, conical horn of the same length. Thorax hemispherical. Third joint inflated, subspherical, and fourth joint slender, inversely conical, as in the similar preceding species. Differs from the latter