Zoology.] NATURAL HISTORY OF VICTORIA. \JPolyzoa. 



Plate 58, Fig. 3. 

 MENIPEA CYATHUS (Wyv. Thomson). 



Description. — A pair of cells in an internode, with three at a bifurcation ; 

 connecting tube single ; aperture of cell oval, oblique ; 3 to 6 long" spines, several 

 of which are pod-like, articulated to the upper and outer margin ; opercular spine 

 springing from the upper and inner margin of the aperture and pointed downwards, 

 divided into two or more processes. Avicularium opening opposite the upper third 

 of the opening. 



Reference. — Wyville Thomson, Dublin Natural History Review, vol. v. 

 (1858), p. 143, pi. xv., figs. 10, 10a. 



Queenscliff. 



M. cyathus differs from the other species here described in the 

 connecting tubes being long and single. The cells project con- 

 siderably ; the aperture is oval or elliptical ; the calcareous plate 

 is reduced to a simple marginal ring. From the upper cell there 

 are usually 6 spines and from the lower 4, but the number is not 

 constant. Several are usually very large and pod-like. The 

 opercular spine is directed downwards and outwards from the 

 upper and inner part of the margin ; in the upper of the two cells 

 of an ordinary internode and in the median one at a bifurcation it 

 is usually simply bifid, and in the others each branch generally 

 again divides so as to form four points. The avicularium is of 

 considerable size, and opens opposite the junction of the middle and 

 upper thirds of the aperture. Besides the lateral avicularia there 

 is occasionally a sessile avicularium in front between the cell 

 apertures. In the lower part of the front of the upper of two cells 

 of an internode, there is constantly a round mark with an annular 

 margin from which a radicle tube occasionally springs. 



Explanation of Figures. 



Plate 58. — Fig. 3, specimen, natural size. Fig. 3a, small portion, magnified ; small sessile 

 avicularia are shown on the front of three of the internodes, and in the internode of bifurcation 

 a radicle tube is also seen. Fig. 3b, single internode, more highly magnified ; in addition to the 

 constant round mark there is in this specimen another similar mark immediately below the 

 anterior sessile avicularium. 



Dec. vi. [ 33 ] E 



