Rhopalocanium varietas, Bury, 1862, Polycystins of Barbados, pl. xvii. fig. 7.
Shell slenderly conical, with five deep strictures. Length of the six joints = 2 : 5 : 4 : 3 : 3 : 6. Cephalis hemispherical, with a stout conical horn of twice the length. Thorax campanulate, with three large, triangular, widely divergent wings or ribbed solid spines, nearly as long as the shell. The breadth of the joints increases gradually; the last joint is the broadest, with wide open mouth. Pores subregular, circular.
Dimensions.—Length of the shell (with six joints) 0.23, breadth 0.1. Length of the single joints, a 0.02, b 0.05, c 0.04, d 0.03, e 0.03, f 0.06.
Habitat.—Fossil in Barbados.
8. Stichopilium pectinatum, n. sp.
Shell slenderly conical, with nine sharp strictures. All ten joints have nearly equal length, and increase gradually in breadth; the last joint is the broadest, and twice as long as each of the others, with wide open mouth. Cephalis subspherical, with a conical horn of the same length. Each joint (excepting the first and the last) bears three lateral, nearly horizontal spines, and the bases of all the spines are connected by three longitudinal, divergent ribs. Pores subregular, hexagonal. (Similar to Stichopera pectinata, Pl. [75], fig. 11.)
Dimensions.—Length of the shell (with ten joints) 0.32, breadth 0.1.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
9. Stichopilium thoracopterum, n. sp.
Shell slenderly ovate, twice as long as broad, with eleven slight annular strictures. The twelve joints (excepting the second) are of nearly equal length, or alternately longer and shorter. The eighth joint is the broadest, one and a half times as broad as the slightly constricted mouth. Cephalis small, hemispherical, with a pyramidal horn of twice the length. Thorax (or second joint) campanulate, twice to three times as long as each of the eleven other joints, with three longitudinal ribs, prolonged into three divergent, slender, free spines. Pores small, regular, hexagonal.