Sagittal ring elliptical, with four pairs of stout arborescent spines (two apical and two equatorial pairs), which are irregularly branched and forked, with numerous thin lateral branches. Apex with a short conical trifid vertical horn. Basal ring thorny, with obliquely descending slightly curved bars. _Dimensions._--Height of the sagittal ring 0.12, breadth 0.09. _Habitat._--South Pacific, Station 300, depth 1375 fathoms. 5. _Semantis distephanus_, n. sp. (Pl. 83, fig. 3). Sagittal ring thin, semicircular, smaller than the thin basal ring, which exhibits two semicircular gates. Both rings are armed with numerous small spines of equal size, which on the former are arranged in two, on the latter in three regular rows. (The basal rod of the sagittal ring, separating the two basal gates, in fig. 3 is, by mistake, not distinctly enough drawn.) _Dimensions._--Height of the sagittal ring 0.06, breadth 0.08. _Habitat._--Tropical Atlantic, Station 348, surface. {958}6. _Semantis spinescens_, Haeckel. _Stephanolithis spinescens_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p.160, Taf. i. fig. 29. _Stephanolithis spinescens_, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 497, Taf. xxxii. figs. 7_a_, 7_b_. Sagittal ring ovate with four pairs of thin, irregularly branched spines, two apical pairs, one on the straight dorsal rod and one on the curved ventral rod. Basilar rod with a posterior and an anterior forked rod (commencing caudal and sternal foot). Basal ring square, with two lateral spines, and two triangular gates scarcely one-third as broad as the ring-gate. An internal ascending procolumna (rod _c__1 in the figure of Bütschli) connects the basal and ventral rods of the sagittal ring. _Dimensions._--Height of the sagittal ring 0.1, breadth 0.07. _Habitat._--Fossil in Barbados. Genus 408. _Semantrum_,[27] n. gen. _Definition._--#Semantida# with four basal pores (two anterior jugular and two posterior cardinal pores), without typical basal feet. The genus _Semantrum_, one of the most important of the NASSELLARIA, arises from the preceding _Semantis_ by duplication of the two basal gates. Behind the pair of coracal rods there arises from the basilar rod of the sagittal ring a third pair of lateral horizontal branches, the scapular rods. These become connected with the coracal rods on each side, and so produce a second posterior pair of basal pores, the "cardinal gates." These are constantly larger than the anterior "jugular gates." Therefore the vertical ring of _Semantrum_ possesses a horizontal basal ring with four very characteristic gates, enclosed by three pairs of lateral curved and connected branches, and these become transmitted by heredity to the majority of the NASSELLARIA. 1. _Semantrum quadrifore_, n. sp. (Pl. 92, fig. 5).