5. Tympaniscus quadrupes, n. sp. (Pl. [94], fig. 4).
Basal ring larger than the mitral ring, with four short vertical three-sided pyramidal feet of equal size (two lateral and two sagittal); the feet are three-sided pyramidal, with finely denticulate median edges, and bear at the base a horizontal thorny spur. Sagittal ring at the apex with a very large cross-shaped horn, bearing two horizontal thorny lateral branches; the horn is supported by an anterior and a posterior arch. Six columellæ strongly curved and dentate.
Dimensions.—Breadth of the shell 0.15, length 0.12.
Habitat.—South Pacific, Station 298, depth 2225 fathoms.
6. Tympaniscus fibula, Haeckel.
Ceratospyris fibula, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xx. fig. 3.
Basal ring of about the same size as the mitral ring, with six large conical descending feet; these are prolongations of the six columellæ, nearly of the same length, slightly divergent, and bear at the base a strong horizontal spur. The six columellæ are strongly curved, spiny, and bear above small arches, which are united with the apical horn of the sagittal ring.
Dimensions.—Breadth of the shell 0.09, height 0.05; total height 0.09.
Habitat.—Fossil in Barbados.
7. Tympaniscus dodecaster, n. sp.