Shell thorny, slenderly ovate, or nearly spindle-shaped, with four sharp strictures. Five joints of different lengths = 3 : 3 : 4 : 6 : 4. The fourth joint is the broadest, and nearly twice as broad as the constricted mouth. Pores small, circular, separated by longitudinal, spiny ribs, regularly disposed in transverse rows; three rows in the first and second, four rows in the third and fifth, six rows in the fourth joint.
Dimensions.—Length of the shell (with five joints) 0.1. Length of the single joints, a 0.015, b 0.015, c 0.02, d 0.03, e 0.02; greatest breadth 0.05.
Habitat.—Arctic Ocean (in different depths), Ehrenberg.
14. Lithocampe tumidula, Haeckel.
Lithocampe tumidula, Haeckel, 1862, Monogr. d. Radiol., p. 318.
Eucyrtidium tumidulum, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. xxii. p. 5, pl. i. fig. 11.
Eucyrtidium tumidulum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 293, Taf. ii. fig. 12.
? Eucyrtidium increscens, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 299.
? Lithocampe increscens, Haeckel, 1862, Monogr. d. Radiol., p. 318.
Shell smooth, nearly spindle-shaped, with four sharp strictures, very similar to the preceding in size and form. It differs in the smooth surface, the absence of longitudinal ribs, and the unequal size of the pores, which form four transverse series in each joint, and are much larger in the broadest (fourth) joint. Proportion of the five joints = 2 : 2 : 3 : 5 : 4.