Definition.—Each cross-arm with two simple branches.
1. Dicranastrum furcatum, n. sp. (Pl. [47], fig. 2).
Arms simply forked, three times as long as broad at their base, with eight blunt ends of the fork-branches. The simple proximal half of each arm about the same size as each branch of the dichotomous distal part, twice as long as broad. Edges of the arms ragged.
Dimensions.—Radius of each arm 0.38, basal breadth 0.12; breadth of the forked part 0.3.
Habitat.—Pacific, central area, Station 271, surface.
2. Dicranastrum dichotomum, n. sp.
Arms simply forked, four times as long as broad at their base; each arm with two blunt branches. The simple proximal part of each arm is three times as long and twice as broad as each branch of the dichotomous distal part. Ends of the arms blunt, truncated.
Dimensions.—Radius of each arm 0.35, basal breadth 0.08; breadth of the forked part 0.2.
Habitat.—South Pacific, Station 281, surface.
3. Dicranastrum cornutum, n. sp. (Pl. [45], fig. 2).