A MONOGRAPH OP THE TERTIARY POLTZOA OP VICTORIA. 41 



W.P. Living. Mediterranean 



This agrees with Busk's description and figure, But I doubt whether it is the 

 Cellepora hippocrepis of Hagenow. The character of the broad plate on the lower 

 edge of the aperture, which is similar to that of the last species, makes it probable 

 that when better specimens are available, it will be found that both species should 

 be referred to Steganoporella or a new genus of which S. patula would be the type. 



Amphiblestrum, Grmj. 



Zoarium encrusting or erect. Area occupying the whole front or with part of 

 the zocecium produced below ; area partly filled in by a membrano-calcareous or 

 calcareous lamina. 



1. A. simplex, n.sp. PI. V., fig. 20. 



Zoarium cylindricnl. Zooecia elongated, quadrate, alternate in longitudinal 

 series, separated by distinct raised margins, the transverse portions of which are 

 prominent ; aperture occupying rather more than half the area, elliptical, extending 

 quite to the margins above, edges smooth and slightly thickened, lamina smooth or 

 faintly granular. No avicularia. 



S.P. ; M.C. 



2. A. bursarium, McGr. PI. V., fig. 22. 



Membranipora rossellii, McG., P.Z.V. 26; A. bitrsarium, McG., T.P.S.Y. ; 

 July, 1886. 



Zoarium encrusting or loosely aclnate. Zooecia elongated, quadrate, with 

 prominent crenulated margins ; about two-thirds of the area filled in by a thin 

 calcareous lamina ; aperture with the lower edge usually oblique, but sometimes 

 straight or irregular. 



S.P. Living. Victoria. 



Closely allied to the recent A. rossellii, from which it differs in the shape of 

 the zooecia. In recent specimens the avicularium, which I have not seen in the 

 fossils, is very peculiar ; it is situated iu a special cell, the mandible nnrrow below, 

 broad and expanded above and directed upwards. Avicularia have not been 

 observed in A. rossellii. Failing these, it is difficult to say whether the two are 

 specifically distinct, as the difference in the zooecia is scarcely sufficient to rank 

 them as such. 



3. A. arethusa, D'Orbigny, sp. PI. V., fig. 21. 



JEschara arethusa, D'Orbigny. P.P.T.C., p. 327; Membranipora arethusa, 



Waters, Q.J.G.S., Aug., 1883, p. 434. 



o 



