4. Peromelissa calva, n. sp. (Pl. [57], fig. 12).
Shell rough, with two ovate joints of somewhat different sizes. Pores irregular, roundish, everywhere scattered. Thorax little larger than the cephalis; from its upper half arise three short conical wings, diverging downwardly or nearly horizontally.
Dimensions.—Cephalis 0.06 long, 0.04 broad; thorax 0.07 long, 0.05 broad.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
Genus 554. Sethomelissa,[[171]] Haeckel, 1881, Prodromus, p. 431.
Definition.—Sethoperida (vel Dicyrtida triradiata clausa) with three divergent latticed lateral wings. Cephalis with a horn (or a bunch of horns).
The genus Sethomelissa differs from the nearly allied Micromelissa in the fenestration of the three lateral wings, and may be derived either from this genus by development of lattice-work connecting the three wings with the shell, or perhaps from Clathrocanium by closing the mouth.
1. Sethomelissa hymenoptera, n. sp.
Cephalis subspherical, thorny, with a bunch of three divergent, larger apical spines. Thorax pear-shaped, with three broad, triangular, latticed wings, the superior edge of which is a horizontal, straight, and stout spine, nearly as long as the thorax. Pores irregular, roundish.
Dimensions.—Cephalis 0.03 diameter; thorax 0.11 long, 0.08 broad.