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



Plate 147, Fig. 2. 



DIASTOPORA CAPITATA (McG.). 



Description. — Zoarium consisting of bilaminate lobes, rising from an encrusting 

 layer, by narrow, stem-like portions, and expanding above ; lamina separated by a 

 thin, calcareous septum, slightly produced beyond the zocecia. Zocecia indistinct 

 at their lower parts, more or less free and tubular above, minutely punctate. 



Reference. — P. H. MacGillivray, Trans. Roy. Soc. Vict., March 1886. 



Port Phillip Heads, Mr. J. Bracebridge Wilson. 



The only specimen I have seen consists of a cluster of four 

 lobes, rising from an encrusting layer of zooecia. Each lobe is 

 narrowed and thicker below, expanded, thinner and undulated 

 above, and usually divided into two secondary lobes. The summit 

 of the lobes is flatter than in the last, and cellular from the openings 

 of imperfectly formed zocecia. The zooecia are not so numerous 

 on the stem-like portion, but increase in number and prominence 

 upwards, until towards the summit they are considerably elongated 

 to assume a corymbose appearance. In the encrusting part a few 

 of the zooecia are closed, the lid having a minute perforation in its 

 centre. 



These two species are interesting, as clearly showing the unstable 

 nature of the characters on which the genus Mesenteripora, as pro- 

 posed by Blainville and generally adopted, is founded. Mr. Hincks 

 has also, in the British Marine Polyzoa, united the two genera. 



Explanation of Figures. 

 Plate 147. — Fig. 2, specimen, natural size. Fig. 2a, one of the isolated lobes, magnified. 



Plate 147, Fig. 3. 



DIASTOPORA BICOLOR (McG.). 



Description. — Zoarium adherent, nearly circular, consisting of three parts : 

 a central elevated portion composed of perfect zooecia, surrounded by a broad fringe 

 of imperfectly developed zooecia, beyond which is a thin calcareous lamina; central 

 portion red, much raised, flat and depressed at the centre; the remaining parts glassy. 



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