A MONOGRAPH OP THE TERTIARY POLTZOA OP VICTORIA. 119 



Internodes with 9-17 zooecia, the number usually being nine, finely punctate. 

 Zocecia closely adnate ; thyrostome slightly produced and turned forwards, circular, 

 with a sharp denticle from the outer and upper edge immediately behind the margin 

 of the orifice. Ooecia pyriform, on the front of the internodes. Lateral branches 

 springing from the base of the second zooecium on one side immediately above the 

 thyrostome of the first. 



S.P. ; M.C. ; B.B. A common living Australian species. 



In the fossils the thyrostomes are a good deal worn and the characteristic 

 process is consequently not usually present. In some specimens, however, it is well 

 shewn. In living specimens the joints are black. 



4. C. eburnea, Linn., sp. PL XVI., fig. 10. 



C. eburnea, Busk, B.M.C., III., 4; Hincks, B.M.P., 420; Busk, O.P., II., 5; 

 C. tnargaritacea, Busk, B.M.O., III., 6. 



Internodes with 8-15 zooecia, finely punctate. Zooecia closely adnate ; thyro- 

 stome turned forwards and slightly produced, circular, entire. Branches originating 

 from the side of a zooecium, varying from the second to the fourth, immediately 

 below the orifice. 



M.C. ; B.B. Living. Europe, North America, New Zealand, Australia. 



This seems to be identical with Busk's C. margaritacea, which occurs rarely at 

 Port Phillip Heads. In the recent specimens the joints are pale-coloured, not black 

 as in C. acropora and C. denticulata. The branches are occasionally very slender. 



5. C. sccdaris, n.sp. PI. XVI., fig. 1. 



Internodes very long and slender, with upwards of twenty zooecia, the surface 

 minutely punctate ; crossed below the thyrostomes by small, slight, transverse 

 elevations. Zooecia indistinct ; thyrostome circular, slightly exserted and turned 

 forwards and upwards. Dorsal surface finely punctate, crossed at intervals by small 

 transverse elevations similar to those in front. Branches originating by a very wide 

 articulation from the side of a zooecium. 



C.B. 



6. C. setosa, McG. PI. XVI., figs. 6, 11. 



C. setosa, McG., P.Z.V., 39. 



Branches very slender. Internodes, with 4-10 zooecia, finely punctate. Zooecia 

 very slender, distinct, closely adnate ; peristome produced, turned forwards and out- 

 wards beyond the edge of the internode ; thyrostome circular, with a long hollow 



