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



also is obliterated. There is usually an elliptical avicularium on 

 the front of the cell, towards the upper part, either vertical or 

 oblique, sometimes nearly central, but oftener to one side. In 

 some specimens numerous other avicularia are found, often on 

 calcareous elevations. The mandibles are of various forms, pointed, 

 spatulate, or semilunar, one of the last frequently situated above a 

 fenestra. The beaded line of the ovicell is thick, the vertical part 

 extending to its summit, where its clavate extremity is occasionally 

 slightly elevated. Small oval or elliptical avicularia are scattered 

 irregularly over the back, sometimes with triangular mandibles, 

 and occasionally one of the latter of a larger size is found at the 

 base of a fenestra. 



In young cells there are frequently two long, hollow, jointed 

 spines attached at the upper margin of the mouth. In older cells, 

 and occasionally in younger ones, there is an enormous spine on 

 one side articulated to an elevation of the peristome. These spines 

 are of peculiar structure (first pointed out by Hincks), consisting 

 of segments narrower at the base, expanding upwards, and each 

 segment fitting into the one below, somewhat like the joints of an 

 Equisetum. 



A marked variety, which I have named sinuata, is usually 

 found surrounding the stems of black algse, and attains a size of 

 about 2 inches by 1 to 1J. In this the polyzoary is much thicker 

 and denser. The sinus in the lower lip is much wider and deeper, 

 and the oral avicularium is larger. The jointed spines, which are 

 commonly present, are of great size ; the first joint is very long, 

 the succeeding ones much shorter. The ovicells are broader, and 

 the vertical beaded line is frequently elevated towards its upper 

 extremity. The avicularia are usually very numerous, and are 

 frequently raised on calcareous eminences. They vary much in 

 shape, and the mandibles are often broadly spatulate. The back is 

 densely granular, the vibices little prominent, and the avicularia 

 very few. 



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