Zoology.-] NATURAL HISTORY OF VICTORIA. [Poli/zoa. 



Description. — That of the genus. 



Reference.— P. H. MacGillivray, Tr. Roy. Soc. Vict., Nov. 1886. 



Port Phillip Heads, Mr. J. Bracebridge Wilson. 



Of this very curious species I have only one good specimen, 

 for which I am indebted to Mr. Wilson, and two or three 

 imperfect fragments. The zoarium is small, branched, bilaminate. 

 The youngest zooecia, and those at the margins of the branches, 

 have one side produced into a long point, with a small avicularium 

 on the inner surface at the summit. As growth advances, the 

 summit disappears, and the mouth becomes svirrounded by a tumid 

 peristome, with the avicularium usually on the outer part of the 

 ring. The pointed process, with its surmounting avicularium, 

 seems to be formed befoi-e the operculum, as in the zooecia 

 sho^ving these parts it cannot be detected. In a few older zooecia, 

 where the peristome is developed into a thick, circular ring, the 

 internal mouth can be seen with a sinus on its superioi- lip, that 

 is, towards the uppe7- end of the branches. On the basal side of 

 the mouth is a perforated plate, covering the ooecium. In young 

 zooecia the ooecium appears first as a cupped elevation, which 

 becomes covered by a perforated plate, and gradually sinks into 

 the substance of the zooecium. The most curious circumstance 

 is that, although the ooecium appears to be below the mouth, it 

 is really above it, owing to the peculiar reversal of the mouth. 



Pcecilopora is allied to Leki/thopora, but differs in the absence 

 of the long, tubular peristome, and in the mature ooecia being 

 immersed. 



Explanation op Fiquhes. 



Plate 156. — Fig. 11, specimen, natural size. Fig. 11a, portion from tiie growing edge, 

 magnified. Fig. Hj, portion from the extremity of a brancli, magnified, one of tlie zooecia 

 allowing tlie internal or primary mouth. Fig. lie, another portion, showing the growth of the 

 ocecium. 



I am indebted to Mr. MacGillivray for the specimens and 

 descriptions of the above Polyzoa. 



Frederick McCoy. 



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