92 A irOXOGUAl'lI OF THE TERTIARY POLTZOA OF VICTORIA. 



tliyrostomc subcircular by the development of the peristome contracted downwards, 

 with a squared denticle in the lower lip ; scA^eral spines on the upper margin ; a 

 small avieiilaiium in front of the denticle, on the upper part of a bullatc projection 

 t)eeiip\ iiiu' (he ])ortion of the zort'cium immediately helow llie (hyrostome. Ocecia 

 small, ii'lohular, smooth, with taint radiating linos. 



M.C. ; W.P. (W.) A common living Australian species. 



5. P. innocua, n.sp. PI. XII., fig. 13. 



Zoa>eia elongated, separated hy narrow raised lines, with a row of long, narrow, 

 deep areolie along the margins, sometimes almost meeting in centre ; tliyrostomc 

 hu'ge, elongated, suhquadrat(^ hut roanded above, with a very large, deep, squared 

 median denticle and a small acute one on each side; a small avicularium in the 

 lower lip nl' llu; peristome. Ooecia small, depressed, punctured. 



B.;M. 



Smittia, Hincks. 



Tliyrostomc semicircular, Avith a square denticle (lyrula) in the lower margin ; 

 secondary aperture elongated, the peristome raised on the sides and forming a spout- 

 like channel below, in which is usually lodged an avicularium. 



1. S. transversa, n.sp. PI. XII., fig. 14. 



Zoarium l)ilaminate. Zooecia quadrate (h- hexagonal, separated by narrow 

 raised lines, nearly fiat, granular, especially in a line immediately within the 

 margin, and with numerous small round perforations ; thyrostome lofty, arched 

 above, contracted below, with a dee]) rounded sinus in the loAver lip formed by the 

 projection of a dentich^ on each side ; a broadly linear avicularium situated trans- 

 versely immediat(^ly beloAV the thyrostome. Oa3cium large, convex, occupying 

 greater part of the zo(i!cium on which it is placed, granular and punctured. 



B.E. 



2. S. depressa, n.sp. PL XII., fig. 15. 



Zooecia large, ovate; margins much thickened and raised, the junction of 

 those of contiguous zocecia indicated by a faint line; surface depressed, flat, Avitli 

 numerous large pores ; thyrostome large, lofty, arched above, with a deep sinus, 

 which is narrowed above and rounded at its extremity. 



M.C; B. 



When the front wall is examined from behind, a small jiointed median denticle 

 is seen. 



