Zoology.} NATURAL HISTORY OF VICTORIA. [Polyzoa. 



Plate 106, Fig. 1. 



AMPHIBLESTRUM PUNCTIGERUM (ITincks). 



[Genus AMPHIBLESTRUM (Gray). (Sub-king. Mollusca. Class Tolyzoa. Order 

 Infundibulata. Sub-order Cheilostomata. Fam. Membraniporidse.) 



Gen. Char. — Zoarium encrusting. Zooecia with the aperture occupying the whole front 

 or with part of the zooecium produced below; aperture partly filled in by an additional 

 membranous or usually calcareous lamina.] 



Description. — Zooecia variously shaped, separated by raised smooth margins; 

 aperture occupying' the whole front, except a very narrow space below and at the 

 sides which is rilled in by a thin, calcareous, smooth or faintly granular membrane. 

 Oeccia large, faintly granular, with a mitriform or quadrate portion in front 

 separated try a narrow raised lino. 



Reference. — Hincks, Ann. and Mag. Nat. Hist., July 1881. 



Port Phillip Heads, on algae. 



This seems to be a rare species, as I have only seen two or 

 three not very good specimens. The zooecia are of a large size 

 and very variable in shape. The raised margins are narrow and 

 smooth. There is a very narrow calcareous membrane, sometimes 

 scarcely distinguishable, on the lower part and extending up the 

 sides. The mitriform or quadrate space on the front of the 

 ocecium seems to be caused by a deficiency of the outer layer at 

 this part. 



Explanation of Figures. 

 Plate 106. — Fig. 1, small portion of a specimen, showing the various shapes of the zooecia, 

 the irregularity in extent of the calcareous thickening of the membrane, and three ooecia. 



I have followed Busk (in the Challenger Polyzoa) in considering 

 those Membraniporrc with the membranous aperture partly filled 

 by a thicker chitinous or calcareous lamina as a distinct genus, 

 and have adopted his name derived from Gray. Gray, however, 

 originally proposed the name for M. membranacea, which in my 

 opinion ought to be taken as the type of the true Membraniporas, 

 the name having been first applied to it by Blainville. Gray, 

 moreover, makes no reference to an additional thickening of the 

 membranous front, which in met does not exist in M. membranacea. 

 Those species previously described in this work as Membraniporae 

 and which are referable to the present genus are M. umbonata, 



cervicornis, and Rosselii. 



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