Zoology.] NATURAL HISTORY OF VICTORIA. [Polyzoa. 



variety has a very peculiar appearance, being divided into regular 

 longitudinal ridges, the intervening hollows formed by the mouths 

 and depressed centres of the cells. 



Explanation of Figures. 



Plate 95. — Figs. 1 and 2, specimens, natural size. Fig. 3, specimen of var. laxa, natural 

 size. Fig. 4, small portion of fig. 1, magnified. Fig. 5, young marginal cells from another 

 specimen. Figs. 5a, 56, 5c, other cells from same specimen. Fig. 6, cells from var. laza, fig. 

 3, magnified. 



Plate 95, Figs. 7-11. 



RETEPORA AVICULARIS (P. McG.). 



Description. — Polyzoary expanded, convoluted; fenestra? elongated, wider 

 than the interspaces ; cells elong-ated, separated by distinct margins ; mouth arched 

 above ; lower lip with a central loop-shaped mark, frequently perforated below, on 

 each side of which is a triangular projection pointing- upwards; a long spine 

 articulated on each side of the mouth ; operculum rounded ; numerous large 

 avicularia, the rostrum elevated and with strong curved beak, the mandible 

 triangular and pointed; ovicell rounded, prominent, smooth, and entire; dorsal 

 surface smooth, vibicate, with scattered avicularia, with triangular mandibles. 



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



Port Phillip Heads. 



This elegant species attains a size of only about an inch high. 

 It is very light and fragile. The lower lip with its two small 

 triangular denticles, and the loop-shaped mark extending down- 

 wards from between them, is very characteristic. This structure, 

 with the rounded, entire, smooth ovicell, sufficiently distinguishes 

 it from our other species. 



Explanation of Figures. 



Plate 95. — Figs. 7 and 8, specimens, natural size. Figs. 9 and 9a, portions of another 

 specimen, magnified. Fig 9b, outline of avicularium. Fig. 10, a single cell and ovicell. Fig. 11, 

 dorsal surface, half as much magnified. 



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