12. Challengeria havergalli, John Murray.
Challengeria havergalli, John Murray, 1879, in litteris, Narr. Chall. Exp., vol. i. p. 226, pl. A, figs. 13, 13a.
Shell subspherical, slightly compressed. Peristome semitubular, slender, somewhat curved, in the lower half a simple half-cylinder, in the upper half forked, with two divergent teeth, nearly as long as the shell.
Dimensions.—Diameter of the shell 0.1 to 0.15, length of the peristome 0.08 to 0.12.
Habitat.—South Pacific, Station 300, depth 1375 fathoms.
13. Challengeria elephas, n. sp.
Shell ellipsoidal, not compressed. Peristome very similar to that of Challengeron diodon (Pl. [99], fig. 6), from which this species differs mainly in the absence of an apical spine, and in a more constricted mouth. The two conical teeth of the mouth are very large, nearly as long as the shell, straight, and almost parallel, each tooth has a large hole on the thickened base.
Dimensions.—Diameter of the shell 0.22, length of the teeth 0.2.
Habitat.—Indian Ocean, Cocos Islands (Rabbe), surface.