96 
THE VOYAGE OF H.M.S. CHALLENGER. 
Up to the present time the only known species referrible to Melicerita were two, cr 
perhaps three, fossil formfe, viz. : — 
1. Melicerita charlesworthii, Milne- Edwards. 
2. Melicerita angustiloba, Busk. 
(?) 3. Melicerita ( Latereschara ) achates, d’Orbigny. 
Of these the first two are probably of Miocene age, belonging one to the Coralline 
Crag of England, and the second to beds, supposed to be of the same age, in Australia 
and New Zealand. M. d’Orbigny’s species, if it be properly referred to the genus, belongs 
to the Cretaceous epoch. The discovery, therefore, of living forms at a considerable depth 
in the South Atlantic is one of very great interest, though they do not, so far as I can 
perceive, present any advance in organisation. 
(l) Melicerita atlantica, n. sp. (PI. XI Y. fig. 1). 
Character. — Zoarium simple or lobate, probably radicate ; about 0"'25 wide. Areas 
hexagonal, usually arched above. Surface finely granular, sloping gradually and evenly to 
the orifice, which in the fresh state is surrounded at 
some distance by a slender chitinous ring incomplete 
above. Orifice large, central, suboval or oblong ; 
lower border straight or slightly concave. Peristome 
thickened, with a minute internal denticle on each 
side below, none (?) above. Ocecial orifice a crescentic 
slit beneath the upper angle of the area. Avicularia 0. 
Habitat. — Station 320, lat. 37° 17' S., long. 53° 
52' W., 600 fathoms, hard ground. 
In the narrow or ligulate form of the zoarium, 
Melicerita atlantica resembles Melicerita angustiloba, 
though it is somewhat broader. But in essential 
particulars the two differ very widely. In Melicerita 
angustiloba the lower border of the orifice is deeply 
notched on either side, or may be said to present a wide, straight- edged mucro. In 
it also, as in Melicerita charlesworthii, there are two large internal denticles above, 
Bk., appears to be articulated, and that “it should he united with Cellaria ( Salicornaria ),” thus concurring in the view 
I had expressed. But it is by no means on account of the zoarium being articulated that this union should be made. 
It would be impossible to separate generically Melicerita charlesworthii, Milne-Edw., from Melicerita angustiloba and 
Melicerita atlantica , n. sp., the former of which is foliaceous and undoubtedly continuous, whilst the latter two may or 
may not be so The mere fact of articulation, therefore, is of little consequence, nor in fact is it so in the genus 
Salicornaria itself. 
Fig. 15 . — Melicerita atlantica. 
