Zoology.-] NATURAL HISTORY OF VICTORIA. \Polyzoa. 



Plate 97, Figs. 4-6. 

 RETEPORA FORMOSA (P. McG.). 



Description. — Polyzoary expanded, foliaceous, convoluted so as to form large 

 funnel-shaped compartments ; fenestrse rounded or oval, narrower than the inter- 

 spaces ; cells elongated, expanded above, separated by distinct raised lines ; surface 

 minutely granular ; mouth sloping backwards, narrowed below, the thickened lateral 

 margin uniting at an acute angle with the raised cell-margin ; the lower lip straight, 

 with a minute sinus ; operculum higher than broad, slightly contracted below ; 

 usually an elliptical avicularium on the front of the cell ; ovicell large, prominent, 

 with a small beaded band on each side above the aperture meeting at an angle in 

 the middle, and extending vertically upwards to end in a slightly clavate extremity; 

 dorsal surface strongly vibicate, granular, and with numerous elliptical or rounded 

 avicularia close to the edges of the fenestra. 



Reference.— P. H. MacGillivray, Tr. Roy. Soc. Vict., 1883. 



Port Phillip Heads, 10-18 fathoms. 



This beautiful species in appearance and size precisely resembles 

 the munita form of R. monilifera. It is, however, at once distin- 

 guished by the form of the mouth, which slopes backwards and is 

 wide above and contracted below. The lower lip is straight, and 

 has usually a minute rounded sinus, and is destitute of oral avicu- 

 larium. The slightly thickened sides of the mouth unite at an 

 acute angle with the elevated margins of the cells. The operculum 

 is also of a very characteristic shape, in correspondence with the 

 form of the mouth. Besides the avicularium on the front of the 

 cells and those on the back of the polyzoary, there is frequently 

 one with a long pointed mandible opening horizontally inwards on 

 the edge of the fenestrse. An avicularium with a semilunar 

 mandible is also occasionally found above a fenestra in front. 



Explanation of Figures. 



Plate 97. — Fig. 4, specimen, natural size. Fig. 5, portion of a specimen, showing the 

 ovicells. Fig. 5a, dorsal surface, half as much magnified. Fig. 6, small portion of another 

 specimen. 



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