of Edinburgh, Session 1880-81. 
61 
The curious spicules mentioned by Heller as occurring in the 
mantle and branchial sac of this species are present in all the speci- 
mens. Smaller ones are also to be observed in the test. Similar 
spicules occur in a new species of Cynthia still to be described. 
The specimens from Tahiti may turn out to be a new but closely 
allied species. 
Cynthia hispida , n. sp. 
External appearance. — Shape ovate or irregularly circular, flat- 
tened laterally, nearly as broad as long ; dorsal and ventral edges 
strongly convex ; anterior end broadish, straight. Attached by 
the rather narrow posterior end. Apertures both at the anterior 
end, moderately far apart, on short dome-like projections, the ends 
of which are conspicuously four cleft and covered with strong 
echinated hairs, which fringe the apertures ; branchial directed 
anteriorly ; atrial directed dorsally. Surface more or less wrinkled, 
and closely covered with a short down of prickly hairs, which 
occasionally at the posterior end, and most markedly round the 
apertures, increase in size and form large branched bristles. Colour 
dull brown, rather lighter round the apertures. Length, 6'6 cm. ; 
breadth, 5*6 cm. 
Test not thick, leathery, tough; smooth and glistening on the 
inner surface. 
Mantle thick, musculature very strong and close, especially on 
the siphons. 
Branchial sac with nine folds on each side, the ventral folds, or 
those next the endostyle on each side, being very slight, and only 
reaching half-way to the dorsal lamina. The alternate transverse 
vessels wider than the intermediate ones. Internal longitudinal 
bars numerous, about twelve on a fold, and the same number in the 
interspace. Meshes containing each about four stigmata. 
Dorsal lamina formed by very small languets. 
Tentacles compound, about fourteen in number, and all about the 
same length. 
Olfactory tubercle small, but very prominent, situated on a hemi- 
spherical projection, elongated transversely ; both horns coiled in- 
wards. 
VOL. XI. 
I 
