Zoohgy.-] NATURAL HISTORY OF VICTORIA. {Polyzoa. 



Busk's D. costafa, of wliicli I have recently received beautiful 

 specimeus dredged at QueensclifF by Mr. J. B. Wilson, differs in 

 its smaller size and greater number and length of the spines, which 

 extend more than half way across the apertui-es, those of opposite 

 sides interdio'itatino-. 



o o 



Explanation op Figcres. 



Plate 46.— Fig. 3, specimen, natural size. Fig. 3a, front view of cells, magnified. Fig. 36, 

 back view of same. 



Plate 46, Fig. 4. 

 DIMETOPIA SPICATA (Busk). 



[Genus DIMETOPIA (Busk). (Suh-kingrl. Mollusca. Class Polyzoa. Order Infundi- 

 bulata. Sub-Order Cheilostomata. Fam. GemcUariiila?.] 



Gen. Char. — Cells joined back to back ; each pair arising from the next below, and placed 

 at right angles to it. Cells of the pair at a bifurcation disjunct, and each giving origin to the 

 first pair of a branch.] 



DE.scEirTiox. — Cells funnel-shaped, contracted below, e.xpanded above. Aper- 

 ture nearly horizontal or obliqiie, margin shghtly thickened and occupied by a series 

 of stout articulated spines. Ovicell roi;nded, situated at the upper and inner part of 

 the cell, and projecting- above the aperture. 



Reference. — Busk, Voy. Ratt., i., p. 384 ; Cat. Mar. Pol. Brit. Mas., p. 35, 

 pi. xxix., fig;. 1. 



Queenschflf ; Cape Otway ; Portland, ]\Ir. Maplestoue ; not 

 uncommon. 



Foi'ms handsome, dense, whitish tufts, 1 to 2 inches high. The 

 cells are of considerable size, iufundibulate. The aperture is 

 nearly horizontal, or sloping obliquely outwards and downwards ; 

 its margin is occupied by a thickened band, and has a series of 

 usually 4 or more articulated spines ; of these, the outer or 

 median is frequently much larger than the others. The ovicell is 

 rounded or ovoid, and situated above and to the inner side of the 

 aperture. 



Explanation of Figures. 



Plate 46.^Fig. 4, specimen, natural size. Fig. 4a, portion, magnified. Fig. 45, small 

 portion, to show the ovicells, 



Dec. V. [ 33 ] E 



