A MONOGRAPn OF THE TERTIARY POLYZOA OF VICTORIA. 55 



M. Clarhei in Monoporella, a genus to which, as originally defined by Ilincks 

 (A.M.N.H., July, 1881) it certainly does not belong. 



1. 31. centralis, n.sp. PI. VIII., fig. 3. 



Zooeeia broad, hexagonal, with narrow, finely granular raised margins ; surface 

 slightly convex, silvery and very finely granular, with interspersed small, scattered, 

 usually bordered pores ; thyrostome in the upper third but at a considerable distance 

 from the anterior extremity of the zocecium, large, arched above, sti'aight below, 

 slightly contracted towards the base and forming rather more than a semicircle ; 

 peristome thickened and raised. 



M.C. 



A beautiful and distinct species. 



2. M. chn-kei, Tenisou Woods, sp. PL VIII. , figs. 5, 6. 



Eschara clarkei, Tenison Woods, T.R.S.N.S.W., 1876, p. 2 ; Ilonoporella 

 sexangularis, Waters, Q.J.G.S., 1883, p. 43; id. 1885, p. 291. 



Zoarium large, flat, bilaminate and lobed, or foliaceous, with large, distant 

 fenestra;. Zoa?cia hexagonal, distinct, with much-raised margins, the surface 

 depressed and hollowed but rising to the thyrostome, finely granidar ; thyrostome 

 large, raised, arched above, straight or slightly hollowed below, situated close to tlie 

 upper extremity of the zooecium, with a thick, raised peristome. 



M.C; B.R.; W.P. ; M. ; Batesford. 



u 

 Waters refers this to the Eschara se.vangularis of GoldfjBss and Ilagenow, and 



he may be right ; but as there is some doubt I liave retained Tenison Woods' specific 



name, the species indicated by him being clearly identical with that here described. 



The size of the thyrostome varies somewhat. Waters has found zooecial avicularia 



in an Aldinga specimen. They must, however, be very rare, as they do not occur in 



any of the numerous specimens I have examined. 



Pamily Cribrilinid^e. 



Zoarium encrusting or erect. Zoo3cia contiguous or disjunct ; front wall 

 formed by a series of ribs, constituted by modified marginal spines converging to a 

 median line, the intervening fissures remaining open, or forming grooves, or closed 

 at intervals by calcareous cross-bars so as to form perforated furrows. 



The essential character of this very natural family is that the front \\a\\ is 

 formed by the development and overarching of series of marginal spines which meet 

 and coalesce in the centre. The fissures between the ribs so formed may remain 



