1. Plagiocarpa procortina, n. sp. (Pl. [91], fig. 5).
Spines cylindrical, curved, thorny, three to four times as long as the common middle rod. Apical spine and the meeting caudal spine (or the posterior basal spine) somewhat longer and with more numerous thorns than the two paired pectoral (or anterior) spines. From the common base of the latter arises an anterior prolongation of the horizontal middle rod, which in the sagittal plane is curved upwards and corresponds to the sternal foot of many Cyrtellaria. An ascending branch of this spine is opposed to a descending branch of the apical spine, both together forming an incomplete sagittal ring.
Dimensions.—Length of the two larger spines 0.15, of the two smaller 0.12.
Habitat.—Mediterranean (Portofino near Genoa), surface.
2. Plagiocarpa procyrtella, n. sp.
Spines of form and arrangement similar to those of the preceding species, but longer and more branched, six to eight times as long as the shorter common middle rod. The two characteristic opposed branches (the ascending branch of the basal rod and the descending branch of the apical spine), which in the preceding species nearly compose a sagittal ring, are here absent.
Dimensions.—Length of the two larger 0.27, of the two smaller 0.21.
Habitat.—North Atlantic, Iceland (Steenstrup), surface.
Subfamily 3. Hexaplagida, Haeckel.
Definition.—Plagonida with six radial spines.