Zoology.'] NATURAL HISTORY OF VICTORIA. [Polyzoa. 



Plate 59, Figs. 2 and 3. 



BICELLARIA GRANDIS (Busk). 



Description. — Cells large, much expanded above, spreading- outwards, with 

 a large nearly horizontal aperture. A variable number of spines from the outer 

 edge. 



Reference.— Busk, Voy. Ratt., i., 374; Cat. Mar. Pol. Brit. Mus., p. 42, 

 pi. xliv. 



Queenscliff ; Cape Otway, Mr. J. Payter. 



B. grandis differs from the other species in the large size of the 

 cells, in their being very narrow below and expanded widely above, 

 and in the large, nearly horizontal, elliptical opening. There 

 are two marked varieties. In the one there are several spines 

 rising separately immediately behind and below the aperture, some 

 of which occasionally originate together from a wide prolongation 

 of the cell. In this form there is constantly a separate spine about 

 half-way down the back of the cell. The aperture is frequently 

 pointed at its inner end. I have not seen the avicularia. This is 

 the form described and figured by Busk. In the other, the cell 

 is prolonged immediately below the outer margin into a broad 

 process, to the end of which all the spines are attached. There is 

 no posterior spine. The avicularia are similar to those of B. tuba, 

 but are shorter and stouter. I was at first inclined to consider 

 them as distinct species, but as in the first variety the spines 

 frequently spring from a production of the outer part of the cell, 

 and in our ignorance of the structure of the avicularia the only 

 constant difference is in the presence of the posterior spine, I 

 think it is better, for the present at least, to unite them. The 

 second form may be called var. producta. 



Explanation of Figures. 



Plate 59.— Fig. 2, fragment, natural size. Fig. 2a, portion of typical form, magnified. 

 Fig. 26, back of same, snowing the posterior spines. Fig. 3, front view of portion of var. producta, 

 magnified, showing the broad spiniferous extension of the cell and an avicularium. Fig. 3a, back 

 of the same. 



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