Zoology.] NATURAL HISTORY OF VICTORIA. \Polyzoa. 



Plate 26, Figs. 5, 6. 



MEMBRANIPORA LACEOIXII (Savigny sp.). 



Description. — Cells oval or elongated ; margins thick, strongly beaded ; usually 

 a short, blunt spine at either side superiorly. 



Reference. — Flustra Lacroixii (Savigny), Egypt, t. 10, f. 9 ; Busk, Cat. Mar. 

 Pol. Brit. Mus., p. 60, t. lxix., t. civ., f. 1. 



In some specimens of this species the lower part of the cell is 

 filled in by a thick calcareous expansion (Fig. 6a), which extends 

 a considerable distance up the sides, while in others it is entirely 

 wanting, or limited to the inferior angles. Although at first sight 

 these two forms might appear to belong to distinct species, it is 

 not difficult to trace all the gradations between them. In speci- 

 mens dredged from the ledge of sandstone rocks, off Brighton, 

 some have the front of the cell entirely occupied by a thin mem- 

 brane (Fig. 5a), others have merely the lower angles filled by a 

 thicker expansion, while others present the appearance shown in 

 Fig. 6a. The spines on the upper part of the cell are by no 

 means constant ; sometimes they are quite distinct, at other times 

 they appear as slight prominences on the cell-margins, and fre- 

 quently they are altogether absent. 



On shells at Queenscliff and Point Cook, and on sandstone rocks, 

 in 4-6 fathoms, off Brighton. 



Explanation of Figures. 



Plate 26. — Fig. 5, specimen, natural size. Fig. 5a, same, highly magnified, of the variety 

 wanting the thickening at base of cells. Fig. 6, another specimen, natural size. Fig. 6a, same, 

 highly magnified, showing the calcareous thickened margin at base of cells of the variety. 



The above descriptions of Membraniporce have been kindly 

 furnished to me by my friend Mr. P. H. MacGillivray. I have 

 spared no trouble to render the plates as perfect as possible, and 

 the species can be identified from them with ease and certainty. 



Frederick McCoy. 



[35] 



