Page:Scientific results HMS Challenger vol 18 part 2.djvu/861

Rh 9. Cœlodendrum flabellatum, n. sp. (Pl. 121, fig. 6).

Terminal branches flabellate, irregularly ramified, each of the last two fork-branches being divided into four or five diverging straight branches of different lengths; usually the last eight or ten ramules lie in a meridional plane; their end-knobs cap-shaped, with a corona of recurved teeth.

Dimensions.—Diameter of the skeleton 2.0 to 2.5, of the valves 0.25 to 0.3.

Habitat.—North Pacific, Station 235 to 240, surface.

10. Cœlodendrum serratum, n. sp. (Pl. 121, fig. 5).

Terminal branches flabellate, irregularly ramified like the preceding species; it differs from this in the strong compression of the broad, saw-shaped, terminal branches; the two opposite edges (placed in the meridional plane of the flabellum) are finely serrated; their end-knobs with a corona of diverging teeth.

Dimensions.—Diameter of the skeleton 3.0 to 3.2, of the valves 0.3 to 0.36.

Habitat.—Central Pacific, Stations 270 to 274, depth 2350 to 2925 fathoms.

Definition.— with an external bivalved lattice-mantle, produced by the anastomosing branches of the hollow radial tubes.

Definition.— with an external bivalved lattice-mantle, produced by the anastomosing terminal branches of the hollow tubes, which are connected in a spherical face.

The genus Cœlodrymus, and the following closely allied genus Cœlodasea, represent together the small subfamily Cœlodrymida, differing from the Cœlodorida in the possession of an outer bivalved lattice-mantle. They exhibit therefore the same relation to the latter, that in the following family the Cœloplegmida bear to the Cœlotholida. The bivalved spherical mantle is composed of a simple lattice-plate in Cœlodrymus, of a spongy framework in Cœlodasea; the anastomosing branches of the hollow radial tubes become connected in the former in a spherical face, in the latter in the form of a spongy framework.