Eucyrtidium eruca, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 70, Taf. x. fig. 13.
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.
Eucyrtidium montiparum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 72, Taf. ix. fig. 11.
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).