A MONOGRAPH OE THE TERTIARY POLTZOA OE VICTORIA. 53 



1. S. magnilabris, Busk. PL VI., figs. 14, 15, 16. 



Membranipora magnilabris, Busk, B.M.C. Pt. II., 62 ; Steganoporella, id. Busk, 

 C.P., Pt. I., 75 ; Steganoporella elegans, Smitt, F.B., Pt. II., 15 ; Steganoporella 

 magnilabris, McGL, P.Z.V., 43; Hincks, A.M.N.H., February, 1887; Waters, 

 Q.J.G.S. 



Zoarium expanded, encrusting or decumbent, or bilauiinate and more erect, or 

 cylindrical. Zocecia separated by thick raised margins higlier anteriorly, quadrate 

 or rounded above ; lamina (separating the superficial and deep chambers in recent 

 specimens) much depressed anteriorly, closely perforated ; opesia large, occupying 

 about half the front of the zooecium, semicircular ; a quadrate calcareous plate 

 rising from the edge of the opesia and connected above with the tubular opening for 

 the polypide, and having a squared depression or opening. 



S.P.; M.C.; B.; C.B.; M. A common recent Australian and New Zealand 

 species ; occurring also in Florida, Japan, and South Africa. 



The fossils differ in some respects from the usual living form. The anterior 

 extremities are mostly rounded, not quadrate ; the opesia in the ordinary zooecia 

 extend quite to the thickened margin above, while in the recent there is a narrow, 

 smooth, calcareous plate or shelf ; the larger (ovicelligerous) zooecia are squared 

 above, and the calcareous lamina occupying the upper part of the opesia is excavated 

 so that the the opesia is nearly triangular. In some specimens the zooecia are much 

 narrower and the shelf on the upper edge of the opesia is distinct as in the recent. 

 In the unilaminate specimens posteriorly the zooecia are distinct, quadrate, convex, 

 and smooth. In one (fig. 143) they are separated by raised margins, and many have 

 a conical hollow process, probably a modified radical tube. I am not sure that the 

 specimen shown in fig. 15, of which I have only a fragment, but which seems to have 

 been cylindrical, does not belong to the closely allied S. neozelanica (Busk). 



2. S. depressa, n.sp. PL VI., fig. 17. 



Zooecia indistinct, with broad flat confluent margins ; area broadly elliptical ; 

 lamina much depressed, with numerous close-set j)ores ; opesia usually semicircular ; 

 a plate rising from the anterior edge of the lamina to the level of the margins, with 

 a large perforation in the centre and a smaller rounded one on each side. 



M. 



3. S. lateralis, n.sp. PI. VI., fig. 18. 



Zooecia arranged alternately in linear series, large quadrate margins, finely 

 granular ; lamina moderately depressed, finely granular ; opesia occupying a third 



