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.
Subfamily 2. Cœlodrymida, Haeckel.
Definition.—Cœlodendrida with an external bivalved lattice-mantle, produced by the anastomosing branches of the hollow radial tubes.
Genus 729. Cœlodrymus,[[345]] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. 12, p. 6.
Definition.—Cœlodendrida 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.
1. Cœlodrymus ancoratus, n. sp. (Pl. [121], figs. 9, 10).
Network of the mantle loose, with large, irregular, polygonal meshes; the terminal branches of the forked trees, which communicate at the spherical surface of the calymma, and compose the mantle, are smooth. Spherical surface covered with very numerous and thin zigzag radial filaments, which are about as long as the galea, and bear at the distal end an anchor with two recurved teeth, denticulate at the concave proximal edge (fig. 10).
Dimensions.—Diameter of the spherical lattice-mantle 2 to 2.5, of the valves 0.3 to 0.4.