Page:Scientific results HMS Challenger vol 18 part 1.djvu/801

Rh 4. Dictyocoryne trigona, n. sp.

Arms of equal size and equidistant, lanceolate, three times as long as broad in the middle part, and as the diameter of the triangular central disk; their distal end armed with a strong conical radial spine. Patagium complete, forming an equilateral triangle with pointed corners.

Dimensions.—Radius of the arms 0.2, basal breadth 0.02, distal breadth 0.06.

Habitat.—North Atlantic, Canary Islands, surface.

Definition.—Triangular shell bilateral or irregular, with three arms of different sizes or at different distances.

5. Dictyocoryne charybdaea, Haeckel.

Spongocyclia charybdaea, Haeckel, 1862, Monogr. d. Radiol., p. 472, Taf. xxviii. figs. 5, 6.

Spongodiscus charybdaeus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms at different distances, nearly equilateral triangular, scarcely half as long as the radius of the large circular central disk. Both paired arms touching at their bases, separated by a great distance from the opposite odd arm. Patagium complete, nearly pentagonal. (The illustration in my Monograph, in the coloured plate xxviii., is better than my description, as I had not exactly separated the arms from the patagium.)

Dimensions.—Radius of the arms 0.18, basal breadth 0.08.

Habitat.—Mediterranean (Messina), surface.

6. Dictyocoryne pentagona, Stöhr.

Dictyocoryne pentagona, Stöhr, 1880, Palæontogr., vol. xxvi. p. 118, Taf. vii. fig. 2.

Arms at different distances, club-shaped, little longer than broad at their rounded distal end. Both paired arms smaller and more approximate than the opposite odd arm. Patagium complete, very large, enveloping the whole shell, and forming a pentagon with rectilinear base and transverse constriction, and with five rounded corners.

Dimensions.—Radius of the arms 0.1 to 0.15, middle breadth 0.04.

Habitat.—Fossil in the Tertiary rocks of Sicily, Grotte, Stöhr.

7. Dictyocoryne agrigentina, Stöhr.

Dictyocoryne agrigentina, Stöhr, 1880, Palæontogr., vol. xxvi. p. 118, Taf. vii. fig. 1.

Arms at different distances, club-shaped, about twice as long as broad, and smaller than the large triangular central disk. Both paired arms smaller and more approximate than the opposite odd