Stylactis triangulum, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 320; Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. viii. fig. 9.
Stylactis triangulum, Stöhr, 1880, Palæontogr., vol. xxvi. p. 113, Taf. vi. fig. 2.
Distance between the paired arms about two-thirds as large as their distance from the odd arm. All three arms nearly of the same size and form, about one and a half times as long as broad, nearly as broad at the base as at the blunt rounded end. Patagium incomplete, with convex chamber-rows, enveloping about two-thirds of the arms.
Dimensions.—Radius of all three arms 0.15, basal breadth 0.05, terminal breadth 0.06.
Habitat.—Pacific and Atlantic, Stations 253, 272, 354, surface; also fossil in the Tertiary rocks of Barbados and Sicily.
4. Euchitonia cruciata, Stöhr.
Euchitonia cruciata, Stöhr, 1880, Palæontogr., vol. xxvi. p. 111, Taf. v. fig. 7.
Distance between the paired arms about one and a half times as large as their distance from the odd arm, which is a little larger. Length of the arm nearly equals twice the breadth, which is the same at the base and at the rounded blunt ends. Patagium incomplete, with concave chamber-rows, enveloping only the base of the arms, and forms between them three other smaller arms; therefore the whole shell forms six angles with six alternating arms.
Dimensions.—Radius of all three arms 0.15, basal breadth 0.05.
Habitat.—Fossil in Tertiary rocks of Sicily, Grotte, Stöhr.