Page:Scientific results HMS Challenger vol 18 part 2.djvu/330

1206 8. Lithomelissa thoracites, Haeckel.

Lithomelissa thoracites, Haeckel, 1862, Monogr. d. Radiol., p. 301, Taf. vi. figs. 2-8.

Lithomelissa thoracites, R. Hertwig, 1879, Organism. d. Radiol., p. 76, Taf. viii. fig. 1.

Shell smooth, with deep collar stricture. Cephalis ovate, with two divergent, slender, conical horns, of about half the length; a major oblique occipital horn on the posterior face, and a minor, nearly horizontal horn above the collar stricture, on the anterior face. Thorax about as large as the cephalis, truncate, ovate. Pores of both joints irregular, roundish, of different sizes. From the upper half of the thorax, below the collar stricture, there arise three slender, conical divergent feet, about as long as the cephalis. Mouth truncate, wide open, not constricted. On the numerous varieties of this common species compare my Monograph, on the structure of the ovate central capsule (enclosed in the cephalis), Hertwig, ''loc. cit.''

Dimensions.—Cephalis 0.05 to 0.08 long, 0.04 broad; thorax 0.03 to 0.05 long, 0.05 to 0.07 broad.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.

9. Lithomelissa mediterranea, J. Müller.

Lithomelissa mediterranea, J. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 45, Taf. vi. fig. 11.

Lithomelissa mediterranea, Haeckel, 1862, Monogr. d. Radiol., p. 302.

Shell smooth, with sharp collar stricture. Relative length of the two joints = 4 : 5, breadth = 4 : 5. Cephalis campanulate, conical, with two divergent small conical horns, a major occipital subvertical horn near the summit, and a minor sub-horizontal frontal horn near the collar stricture. Thorax truncate, ovate, little larger than the cephalis. From its lower part there arise three short conical, divergent feet, scarcely half as long as the cephalis (in Müller's figure one of them is seen shortened, opposite to the frontal horn). Pores irregular, roundish, much smaller in the cephalis than in the thorax. Mouth wide open, not constricted.

Dimensions.—Cephalis 0.04 diameter, thorax 0.05 diameter.

Habitat.—Mediterranean (French shore), J. Müller, surface.

10. Lithomelissa bicornis, Ehrenberg.

Lithomelissa bicornis, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 297, Taf. ii. fig. 7.

Shell smooth, with deep collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 2. Cephalis hemispherical, with two divergent, stout and straight, pyramidal horns; a larger occipital horn sub-vertical near the summit, and a smaller oblique frontal horn near the collar stricture. Thorax subspherical, twice as large, with larger irregular, roundish pores. From its lower half there arise three divergent curved pyramidal feet of about the same length. Mouth constricted, only one-third as broad as the thorax.

Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.06 diameter.

Habitat.—Atlantic, Stations 348 to 353, surface.