Zoology.] NATURAL HISTORY OF VICTORIA. [Polyzoa. 



distinctly visible to the unaided eye. The marginal spines are 

 generally three on each side, short and pointed. 

 Common on algae ; everywhere on our shores. 



Explanation of Figures. 



Plate 25. — Fig. 7, specimen, natural size. Fig. 7a, portion of same, highly magnified, 

 showing the immensely lengthened vibraculum. 



Plate 25, Fig. 8. 



MEMBRANIPORA CERVICORNIS (Busk). 



Description. — Cells oblong* or oval, lower part filled in by a calcareous expan- 

 sion ; on either side of the aperture superiorly is a large branched process. Ovicell 

 shallow, galeate, frequently surmounted by a small avicularium. 



Eeierence. — Busk, Cat. Mar. Pol. Brit. Mus., p. 60, t. c. f. 3. 



This species is at once distinguished by the peculiar processes, 

 branching like stags' horns. The Australian form differs slightly 

 from that described and figured by Professor Busk. It has no 

 marginal spines besides the superior branched ones, the branches 

 of which are more slender and do not inosculate with those of the 

 opposite spine, and the color of the polyzoary is white or brownish- 

 white. 



Williamstown, on Sargassum ; plentiful. 



Explanation of Figubes. 



Plate 25.— Fig. 8, specimen, natural size. Fig. 8a, same, magnified. Fig. $b, portion of 

 same, more highly magnified to show more clearly the branching processes. Fig. 8c, ovicell 

 magnified. 



Plate 26, Fig. 1. 

 MEMBRANIPORA DISPAR (P. MacGil.). 



Description. — Cells oblong-, of two sizes, arranged in concentric series, a row 

 of large cells being followed by two rows of short; mouth arched; a thick, blunt, 

 hollow spine on each side of the mouth, in the larger cells of enormously dispro- 

 portionate size. 



Reference.— -P. MacGillivray, Trans. Roy. Soc. Vict., 1868. 



[32] 



