Page:Scientific results HMS Challenger vol 18 part 2.djvu/603

Rh Dimensions.—Length of the shell (with eight joints) 0.2, of the fourth joint 0.02, of the eighth joint 0.04; breadth of the fourth joint 0.04, of the eighth 0.08.

Habitat.—Fossil in secondary rocks of North Germany (chalk of Brunswick, &c.), Zittel.

Definition.— (vel Stichocyrtida eradiata aperta) with a middle constriction of the shell, the upper half of which is conical, the lower cylindrical. Mouth truncate. Cephalis with a horn.

The genus Stichocorys is intermediate between the two preceding and the two following genera; the upper half of the shell with the three first joints is conical, the lower half with the fourth and the following joints cylindrical, of equal breadth. The third joint of the shell (or the abdomen of Theoconus) is constantly the largest, being broader than all the other joints. Stichocorys is a very common and characteristic form, and may be derived from Theoconus by development of a post-abdomen.

1. Stichocorys wolffii, n. sp. (Pl. 80, fig. 10).

Shell in the upper half (with three joints) thorny, in the lower half (with two joints) smooth. Pores of the former double-contoured, in subregular, transverse rows. Pores of the latter smaller, simple, scarcely scattered. Cephalis with a pyramidal horn of the same length. Thorax with prominent, longitudinal divergent ribs. Dedicated to Caspar Friedrich Wolff (Halle, 1759).

Dimensions.—Length of the shell (with five joints) 0.16; breadth of the third joint 0.08, of the fourth 0.05.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

2. Stichocorys panderi, n. sp. (Pl. 80, fig. 7).

Shell in the upper conical half (with three joints) spiny, in the lower subcylindrical half (with three joints) smooth. Pores small, circular, irregularly scattered, simple. Cephalis with a conical horn of the same length. No longitudinal ribs. Dedicated to Christian Pander (Würzburg, 1817.)

Dimensions.—Length of the shell (with six joints) 0.18; breadth of the third joint 0.08, of the fourth 0.05.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

3. Stichocorys baerii, n. sp. (Pl. 80, fig. 8).

Shell in the upper conical half (with three joints) spiny, in the lower cylindrical half (with three joints) sulcate, with prominent longitudinal ribs, alternating with longitudinal rows of small pores.