100 ALDER, ON NEW BRITISH POLYZOA. 
British Museum. <A broken fragment of it, lent me for exa- 
mination, proves, as I had expected, that it is only an aber- 
rant variety of the C. cervicornis of British authors. 
PaLmi CELLARIA, Hoy. genus, 
Polyzoary erect, calcareous, inarticulate, cylindrical, 
smooth, branching dichotomously. Cells disposed in four 
longitudinal alternate series, those in the two opposite series 
being on the same level. Apertures circular, opening ver- 
tically, within a slight concavity (Pl. ITI, fig. 4,) with a broad 
projecting, palmate expansion in front, bearing an ayicu- 
larium. 
This genus is somewhat intermediate between Cellepora and 
the Quadricellaria of Sars. With the former it agrees partially 
in the form of the aperture, but it differs in the simplicity of its 
general structure and the regular arrangement of its cells, 
which have not the heaped appearance more or less character- 
istic of that genus in its adult state. With Quadricellaria it 
agrees in the arrangement of the cells, but differs in the 
form and position of their apertures. No ovicells have yet 
been observed. 
PALMICELLARIA ELEGANS, n. sp. (Pl II, figs. 1—4.) 
Polyzoary very slender, of ivory whiteness, two or three 
times dichotomously branched nearly on the same plane, 
and of equal thickness throughout, or expanding very slightly 
towards the top; composed of four longitudinal rows of cells 
alternately with each other, the opposite cells correspond- 
ing; they are oblong-ovate and smooth, young cells showing 
some minute perforations round their margins ; the apertures 
are circular and sunk in a slight depression, with a long, 
curved, and expanded rostrum in front, bearing a circular 
avicularium on the centre of the upper surface. Height 
_{,ths of aninch; breadth of stem -,th inch. 
For the opportunity of describing this elegant and grace- 
ful little coral I am indebted to my friend Mr. Norman, 
who dredged it last summer in from eighty to ninety fathoms, 
eighteen to twenty-five miles north of Burraforth light- 
house, the most northern point in Shetland. Palmicellaria 
elegans is distinguished, not less by the simplicity of its 
structure than by the gracefulness of its form. It is of 
