A MONOGRAPH OF THE TERTIARY POLYZOA OF VICTORIA. 13 



14. C. hastctta. Busk. PI. I., figs. 21, 22, 23. 



C. hastata, Busk, B.M.C., Pt. I., 7 ; id. C.P., 10 ; McG., P.Z.V., 24. 



Zocecia ovate ; front with a scutiform area, having on each side 5 - 9 fenestras, 

 between which are usually lines or fissures converging to a central line ; thyrostonie 

 straight below, with an internal denticle (usually absent) on either side. 



S.P. ; M.C ; B.R. and W.P. (W.). A common living Australian species. 



The large lateral processes, so characteristic of the recent specimens, are 

 wanting in the fossils, having been broken or worn oft', but I think there can be 

 little doubt of the identification. It is a very variable species, recent specimens 

 dift'ering in the form and size of the zooecia, the form of the scutiform area, the 

 number and appearance of the fenestra, and the shape and size of the lateral 

 processes. Normally the fenestras are the openings of short horizontal tubes, but 

 these are frequently indistinguishable, and the pores seem to open directly inwards. 

 The lateral processes usually have the supra-avicularian portion pointed upwards, 

 while in a common very massive form, which I was at one time inclined to describe 

 as a new species^ tlie lateral processes are thick, Ijlunt or rounded above and 

 considerably turned forwards. In the fossils the opening of the fenestras into tubes 

 is usually very apparent. The zoa^cia are generally narrower than in the recent. 

 They are also frequently produced above the thyrostonie, and there is then a distinct 

 narrow longitudinal ridge, which is absent in the recent specimens, owing to the 

 thyrostonie being situated almost at the summit of the zocecium. 



15. C. retroversa, n.sp. PI. I., fig. 24. 



Zooecia broadly ovoid or elliptical ; a row of fenestra;, about six on each side, 

 round the margin, with grooves radiating from the central line ; thyrostonie large, 

 lofty, straight below; lateral processes very broad, extending the whole length of the 

 zooicia and turned backwards ; a marginal avicularium at each upper angle opening 

 directly outwards. 



M.C. 



Allied in structure to C. crihraria, but distinguished at once by the broad, entire, 

 retro verted lateral processes. 



16. C. marginato, Waters. PI. I., figs. 25, 2G, 27. 



C. marginata, Waters, Q.J.G.S., August, 1881, p. 317. 



Zocecia elongated, nearly cylindrical ; thyrostonie large, straight below ; 8 or 9 

 fenestras enclosed by a narrow, prominent, raised ridge ; zooecia produced above the 



