ASCIDIOIDA. 
473 
L. spiniferci, Hassall. 
Dublin Bay, Dr. Hassall. 
L. violacea, Forbes. 
North of Ireland, Mr. Hyndman. 
L. concinna , Busk, MSS. 
North of Ireland, Mr. Hyndman. 
L. labrosa, Busk. MSS. 
North of Ireland, Mr. Hyndman. 
Genus Membranipora. 
M. pilosa, Ellis. 
Very common on Algae, shells, and around the Irish coast. 
Var. B, with the long bristle abortive, common also. 
Ballantrae, Ayrshire ; Freshwater Bay, Isle of Wight, W. T. Invest- 
ing an Algae in my collection from Van Diemen’s Land, W. T. Youghal, 
Miss Ball. Var. stellata. 
Stellata, or of a sub-stellate outline, cells without hairs or setae. 
Polypidom of a light sandy colour, incrusting the larger marine Algae 
in somewhat of a stellate form ; a few inches in diameter ; aperture of the 
cells without hairs or bristles (like those of M. pilosa and M. spongiosa, 
Temp.), but beset with spines or denticles, varying much in number, one 
at the base generally exceeding the others in magnitude. Along the 
centre of each ray extends a series consisting of a few rows of oblong or 
roundish-oblong cells, on either side of which are transverse rows of 
square and roundish cells considerably larger than those which constitute 
the central portion ; “ parietes of the cells prettily punctured.” This 
description applies to the species in its most perfect state. When the 
stellate figures coalesce — which they rarely do — so as to cover the surface 
of the plant, the form and arrangement of the cells, as just mentioned, 
are generally preserved. When deviations from this arrangement do 
occur, the general form of the Zoophyte is the most obvious character. 
This species first occurred to me in Belfast Bay, in September, 1833, when 
a quantity of tangle, Laminaria digitata, had been thrown ashore, on the 
broad leaves of which its stellate form at once arrested my attention. In 
Strangford Lough I similarly found it afterwards ; and more recently in 
Scotland, near Ballantrae (Ayrshire), on Fucus serratus, but not in per- 
fection on this plant, whose leaves are too narrow to permit its perfect 
growth : on the shore at Leith too I have gathered it ; and on a specimen 
of Nitophyllum Gmelini, from Sidmouth, favoured me by Dr. Greville, it 
appears. Its distribution .would thus seem to be extensive. 
I lately ascertained that it had been found by Dr. Drummond, many, 
perhaps thirty, years ago, at Larne. 
M. membranacea , Flem. 
Flustra tuber culata , Johnst. B. Z., 289, pi. 34, f. 9. On shells and stones 
from Belfast and Strangford Loughs, W. T. 
Often inside our largest dead univalve shells. On stones and Algae. 
On Pectunculus pilosus, from Magilligan, Co. Londonderry. 
