ALDER, ON NEW BRITISH POLYZOA. 101 
small size and very little branched, and is more slender than 
any other member of the family. 
Mr. Norman had previously dredged a small piece of this 
polyzoon in Loch Fyne, but not sufficiently perfect to allow 
of its characters being recognised ; and he has since ascer- 
tained that similar imperfect specimens are in the Johnsto- 
nian collection in the British Museum, labelled Pustulipora 
proboscidea, showing that the species erroneously so named 
in ‘ British Zoophytes’ was described from much worn ex- 
amples of this genus. ‘The P. proboscidea of Milne Edwards 
is quite distinct, and belongs to a different order. 
Genus QUADRICELLARIA, Sars. 
Polyzoary erect, calcareous, rigid, inarticulate, cylindrical, 
dichotomously branched. Cells disposed in four regular 
longitudinal alternate series, immersed; apertures slightly 
tubular (opening laterally), with the upper and lower margins 
a little projecting. Polypides with twelve to twenty tenta- 
cles, the lower ones shortest. 
Professor Sars characterised a genus formed for a Poly- 
zoon that he had formerly described as a Pustulipora. 
The same species has been referred by Prof. Busk to his 
new genus Onchopora, in the family Salicornariade. The 
latter comes nearer to its true affinities. The species, how- 
ever, seems entitledto generic rank, and is now, I think, 
more correctly placed among the Escharide.* 
QUADRICELLARIA GRACILIS, Sars. (Pi. I, figs. 9—12.) 
Polyzoary slender, white, much branched dichotomously, 
the branches cylindrical, nearly linear, and tapering a little 
towards the extremities. Cells arranged in four longitudinal 
rows, alternating with each other, so that the two cells 
on opposite side of the branches are on the same level. 
Apertures nearly circular, slightly tubular and bilabiate. 
There is a small tubular orifice below the mouth, and large 
oval radiating perforations surround the margins of the 
cells, the surface of which is finely striated in an undulating 
manner. Two, or sometimes four, small circular avicularia 
are seen at the sides of the cells, on a line with the perfora- 
* Mr. Busk informs us that the name Quadricellaria has been already 
used by D’Orbigny for a genus of chalk fossils, and will have to be changed, 
