Zoology.] NATUEAL HISTORY OF VICTORIA. \Polyzoa. 



surface is frequently marked by narrow raised lines which in many 

 cases seem to mark the lateral boundaries of the incurved plate. 

 The dorsal surface is sub-granular, with numerous, sharply-raised 

 vibices. The avicularia are very sparse, small, and with triangular 

 mandibles. They are mostly situated close to the margins of the 

 fenestrse. The operculum differs from that of all the other 

 Victorian Eetepores in having the occlusor muscles attached to 

 small round impressions at a distance from the margins. 



Explanation of Figures. 

 Plate; 98. — Fig. 1, specimen, natural size. Fig. 2, group of young marginal cells, from 

 another, very small, growing specimen, magnified. Fig. 3, small group, showing partially 

 developed ovicells. Fig. 4, group with fully formed ovicells. Fig. 5, portion of the back of 

 the polyzoary, magnified half the dimensions of the other enlarged views. 



Plate 98, Figs. 6-7. 



RETEPORA AURANTIACA (P. McG.). 



Description. — Polyzoary expanded, foliaceous, convoluted; fenestrse elliptical 

 or oval, about the same width as the interspaces; cells quadrate, separated by 

 narrow raised margins ; mouth rounded above, straight below, with a deep narrow 

 sinus, on one side of which is a rounded avicularium ; a long', jointed spine articu- 

 lated on each side of the mouth ; operculum large, much wider than high, hollowed 

 at the sides inferiorly ; usually a round avicularium on the front of the cell ; ovicell 

 large, pyriform, with a vertical, narrow fissure, wider above, and with thickened 

 margins ; dorsal surface strongly vibicate, granular, and with numerous small, 

 rounded avicularia, especially abundant near the fenestras. 



Reference.— P. H. MacGillivray, Trans. Roy. Soc. Vict., 1882. 



Port Phillip Heads. 



The largest complete specimen I have seen is three inches wide 

 by about two in the other diameters. The base of attachment is 

 about an inch long. The avicularium on the front of the cell is 

 by no means constant. The ovicells are abundant, and have a very 

 distinctive appearance ; with growth the vertical slit is sometimes 

 filled in, leaving a slightly prominent ridge. It is an exceedingly 

 handsome species of a beautiful orange colour. 



Explanation or Figures. 

 Plate 98. — Fig. 6, specimen, natural size. Fig. 7, cells near the margin, magnified. 

 Fig. 7a, another portion of the same, showing the ovicells. Fig. 7b, portion of the dorsal 

 surface, magnified to half the dimensions of the others. 



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