16. Eucyrtidium eruca, Ehrenberg.
Shell smooth, slender, ovate, or nearly spindle-shaped, with four sharp strictures. Five joints of different lengths, the third and fourth nearly equal, twice as long as the fifth, one and a half times as long as the second; the fourth joint is the broadest. Mouth little constricted. Cephalis subspherical, with a small, conical horn. Pores small and numerous, subregular, circular.
Dimensions.—Length of the shell (with five joints) 0.12 to 0.14; length of the third and the fourth joints, 0.03 to 0.04, breadth 0.04 to 0.05.
Habitat.—Cosmopolitan; Atlantic, Pacific, in different depths; also fossil in Barbados and Sicily.
17. Eucyrtidium montiparum, Ehrenberg.
Shell rough, nearly spindle-shaped, with five deep strictures. Six joints of different lengths, the third and fourth nearly equal, longer than the fifth and the sixth joints; the fourth joint is the broadest. Mouth slightly constricted. Cephalis very small, hemispherical, hyaline, with a short, conical horn. Pores subregular, circular, twice as broad as in the similar smaller preceding species.
Dimensions.—Length of the shell (with six joints) 0.2; length of the third and the fourth joints 0.05, breadth 0.07 to 0.08.
Habitat.—Fossil in Barbados.
18. Eucyrtidium cienkowskii, n. sp. (Pl. 80, fig. 9).
Shell smooth, subconical, with five distinct strictures. Six joints of different lengths; the third joint conical, one and a half to two times as long as each of the other joints; the fifth joint is the broadest. Mouth wide, very slightly constricted. Cephalis hemispherical, with an oblique pyramidal horn of the same length. Pores regular, circular, in dense transverse rows; five to six rows in each of the three last joints, eight to nine rows in the third joint.
Dimensions.—Length of the shell (with six joints) 0.16, length of the third joint 0.04, of each following joint 0.02; greatest breadth (in the fifth joint) 0.08.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.
19. Eucyrtidium elongatum, Stöhr.
Shell rough, slender, nearly spindle-shaped, variable in size and form, with six to seven distinct strictures. Seven to eight joints of different lengths, often alternately longer and shorter. The second
