Dimensions.—Radius of each arm 0.18, basal breadth 0.04, breadth of the branches 0.02.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
Subgenus 2. Chitonastromma, Haeckel.
Definition.—One odd arm different in size or form from the two other arms, which are paired; distance between them different; fundamental form of the shell therefore a bilateral, isosceles triangle.
3. Chitonastrum jugatum, n. sp. (Pl. [43], fig. 14).
Dictyastrum jugatum, Haeckel, 1881, Prodromus et Atlas (pl. xliii. fig. 14).
Arms very different; odd arm club-shaped, twice as long as broad, at the blunt distal end twice as broad as at the base; its axis is perpendicular to the common axis of both paired arms, which are only two-thirds as long, not so broad, and in the distal half divided into two branches; the anterior branch is straight, nearly horizontal, the posterior shorter and curved backwards.
Dimensions.—Radius of the odd arm 0.2, of the paired arms 0.15; distal breadth of the former 0.08, basal breadth 0.04; breadth of the paired arms 0.04.
Habitat.—South Atlantic, Station 325, surface.
4. Chitonastrum dicranoides, n. sp.