ASCIDIOIDA. 473 



L. spinifera, 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. HjTidman. 



Genus Membranipora. 

 M. jnlusa, 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 Algfe 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 seta^. 



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 31. 2)il<'S(t and 31. 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 roAvs 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 surfoce 

 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, Lamittaria digitata, had been thrown ashore, on the 

 broad leaves of Avliich its stellate form at once arrested my attention. In 

 Strangford Lough I similarly found it afterwards ; and more recently in 

 Scotland, near Ballantrae (AjTshire), on Fiiciis serratiis, but not in ])cr- 

 fection on this plant, whose leaves are too narrow to permit its jjcrfect 

 growth : on the shore at Leith too I have gathered it ; and on a specimen 

 of NitophyUiim Gwelini, 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 Lai'ue. 



31. memhranacca, Flem. 



Fbistra tuhrrcitlata, 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 Fectiinculus pilosus, from Magilligan, Co. Londonderry. 



