1877.]  ANTHOBRANCHIATE NUDIBRANCHIATE MOLLUSCA. 261 
raised openings. Branchiz numerous, small, ramose, non-retractile, 
arranged in 8 bundles at some distance around the thickened, gently 
protuberant anus. Oral tentacles moderately large, fleshy, flattened, 
subcordate in outline, with the border multilobulate. Foot broadly 
rounded and indistinctly grooved in front, narrower and rounded 
behind. 
Colour of the fresh spirit specimen purplish red, mottled with 
white upon the back, and especially on the sides ; at the commence- 
ment of the mantle-expansion along each side are about 12 irre- 
gular, subrhomboid, white blotches 3; with the exception of a distinct 
band of transparent purplish white at the extreme border, the re- 
mainder of the expansion is red with darker radiating streaks. The 
rhinophores are red; the branchiz white, streaked with red; and 
the anus is yellow. Underneath, the surface is chiefly mottled with 
red and white; the sole of the foot is uniform reddish with a 
yellowish edge; and the margin of the mantle is purplish white. 
Length (in spirit) 72 millims., extreme breadth 75. 
Hab. Mauritius. 
No spicules could be found in the mantle. 
HEXABRANCHUS ANEITEUMENSIS, sp. nov. 
H. aneitensis, Bergh [in sched. ]. 
Body oblong-ovate, soft, smooth, depressed. Mantle expanded, 
especially at the sides and behind, with the edge membranous and 
fimbriate. Rhinophores with the upper part short, thick, conical, 
laminated, and recurved ; the pedicels slender; retractile in smoothly 
marginated cavities. Branchie short, soft, tamose, in 7 irregular 
bundles at some distance around the wide anus, the opening of 
which is slightly raised. Oral tentacles flat, fleshy, with deeply 
and many-lobed border. Foot from one third to one half the breadth 
of the mantle, transversely grooved in front, the lateral and posterior 
borders much flattened. 
Colour of the spirit specimens, above, mottled red and white, 
the branchiz streaked with red ; below, the sides and mantle 
covered with reticulating spotted red markings ; the sole of the foot 
uniform reddish. 
Hab. New Hebrides (Aneiteum). 
HEXABRANCHUS MAURITIENSIS, Sp. nov. 
Form elliptic, moderately depressed, smooth. Mantle expanded 
at the sides, with the border thinning out, subcrenulate and fimbriate, 
except in front, where it is rather thickened, and very little of it is free. 
Rhinophores with the upper portion diagonally laminate, conical, 
rather slender, pointed, and directed backwards ; their cavities with 
short, plain, sheathing margins. Branchiz in 7 or 8 non-retractile 
bundles, each containing three or more irregular, short, tripinnate 
plumes, set round at some distance from the anus. Mouth large ; 
oral tentacles moderate, fleshy, leaf-like lobes, with crenulate edges, 
Foot long, truncated in front, extending behind nearly as far as the 
end of the mantle. 
