2. Spongotripus neumayri, Haeckel.
Spongy disk circular, nearly spherical; three radial spines on its margin of equal size and equidistant, pyramidal, nearly as long as the diameter of the disk, and three times as long as broad at the base.
Dimensions.—Diameter of the disk 0.15 to 0.2; length of the spines 0.11, basal breadth 0.04.
Habitat.—Fossil in the Jura of the Alps and in Tertiary rocks of Barbados.
3. Spongotripus strepsiceros, n. sp.
Spongy disk circular; three radial spines on its margin of equal size and equidistant, angular, twice as long as the diameter of the disk, spirally twisted like the horns of Antilope strepsiceros.
Dimensions.—Diameter of the disk 0.15; length of the spines 0.3, basal breadth 0.02.
Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.
Subgenus 2. Spongotripodium, Haeckel.
Definition.—Radial spines of different size or at different distances; triangle either isosceles or irregular.
4. Spongotripus ypsilon, n. sp.
Spongy disk triangular, isosceles, with convex sides; three spines angular, of different size and at different distances; the odd spine straight and twice as long as the two paired spines, which are more approximated and curved concavely one to the other, like 
.
Dimensions.—Diameter of the disk 0.12; length of the odd spine 0.2, of the paired spines 0.1, basal breadth 0.04.
Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.
5. Spongotripus irregularis, n. sp.
Spongy disk circular; three spines conical, irregularly curved, all three of different size, and at irregular distances; once to three times as long as the diameter of the disk; margin of the disk thorny.
Dimensions.—Diameter of the disk 0.1; length of the spines 0.1 to 0.3, basal breadth 0.05.
Habitat.—South Pacific, Station 300, depth 1375 fathoms.
