? Lithopera amblystauros, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 78, Taf. iii. fig. 5.
Shell smooth, with slight collar stricture. Length of the two joints = 3 : 4, breadth = 3 : 4. Cephalis large, ovate, with a conical horn of the same length, small scarce pores, and an internal frontal septum, composed of two crossed beams, a vertical and a horizontal. Thorax little larger than the cephalis, ovate, with irregular, small and scarce pores. (The two figures of Ehrenberg are either incomplete—in Lithopera amblystauros, the cephalic horn, and in Lithopera oxystauros, the basal part of the thorax, being broken off—or they belong to different Botryodea).
Dimensions.—Cephalis 0.03 diameter, thorax 0.04 diameter.
Habitat.—Fossil in Barbados.
Genus 580. Dicolocapsa,[[197]] Haeckel, 1881, Prodromus, p. 433 (sensu emendato).
Definition.—Sethocapsida (vel Dicyrtida eradiata clausa) with a free cephalis, without apical horn.
The genus Dicolocapsa differs from the preceding Sethocapsa in the loss of the apical horn, and therefore bears to it the same relation that Dictyocephalus does to Sethocyrtis.
1. Dicolocapsa microcephala, n. sp. (Pl. [57], fig. 1).
Shell smooth, thin-walled, with distinct collar stricture. Cephalis small, subspherical, with small, crowded pores. Length of the two joints = 1 : 3, breadth = 1 : 3. Thorax also nearly spherical, three times as large as the cephalis, with small, irregularly scattered, circular pores, and much broader bars.
Dimensions.—Cephalis 0.03 diameter, thorax 0.09 diameter.