Genus 650. Lithocampe,[[267]] Ehrenberg, 1838, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 128 (sensu emendato).
Definition.—Stichocorida (vel Stichocyrtida eradiata aperta) with ovate or spindle-shaped shell, the mouth of which is constricted, but not prolonged into a tube. Cephalis without horn and tube.
The genus Lithocampe is the oldest of all "Polycystina," being founded by Ehrenberg in 1838 upon Lithocampe radicula. Afterwards numerous other species, which belong to very different genera, were described by him. In 1862 I attempted to give a more strict definition of this genus in my Monograph (p. 312 to 315), and separated it from the closely allied and often confounded Eucyrtidium by the absence of a cephalic horn. The great number of species afterwards discovered leads to the stricter definition given above.
Subgenus 1. Lithocampula, Haeckel.
Definition.—All joints of the shell (except often the first) are equal or nearly equal in length.
1. Lithocampe eupora, Haeckel.
Eucyrtidium euporum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 291, Taf. iv. fig. 30.
Shell smooth, ovate or subconical, with three deep strictures. Four joints equal in length, gradually increasing in breadth, each with three transverse rows of regular, circular, hexagonally-framed pores; the fourth joint is the broadest. Mouth little constricted, of the same breadth as the third joint.
Dimensions.—Length of the shell (with four joints) 0.08; length of each joint 0.02, greatest breadth 0.06.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms; North Atlantic, depth 3600 fathoms (Morse).