212 Proceedings of the Royal Society of Victoria. 



the aperture in the membranous layer (ectocyst), but also to the 

 aperture in the calcareous layer (cryptocyst), though for the 

 latter the term " opesia " would be more correct. 



S. magni punctata, nom. nov. (PI. XXIV., Fig. 1). 



S. punctata, McG. T.R.S.V., 1895, p. 47. 



Waters. Q.J.G.S., Aug., 1883, p. 440. 

 „ Waters. A.M.N. H., Sept., 1887, p. 201. 



?S. fenestrata, Haswell. Pr. Linn. Soc. N.S.W., 1880, p. 42. 



" Zoarium discoid, convex ; zooecia in irregularly radiating 

 series, wider above, lamina finely granular, inferior and lateral 

 parts depressed, rising to the aperture below which on each side 

 is a large stellate pore ; aperture large, rounded above, straight or 

 slightly hollowed below ; vibracular cells large, with a distinct 

 margin, cribriform. Posterior surface of zoarium with radiating 

 convex ridges, with large round pores, and separated by deep 

 furrows, at the bottom of which are raised lines" (McG.). 



Localities.— Lower beds Muddy Creek (T. S. Hall); Mitchell 

 River and Jimmy's Point (J. Dennant). 



I have given Dr. MacGillivray's description, as it is evidently 

 from a better preserved specimen than mine, of which, however, 

 I have figured four zooecia to compare with the other figures; 

 all the figures are drawn with the camera lucida to the same 

 scale. 



S. punctata, T. Woods. T.R.S. S.A., 1879, p. 9. 

 (PI. XXIV., Fig. 2). 



Zoaria small, discoid, massive, convex or roundly conical, from 

 two to four millimetres in diameter. Zooecia ovate (0.15 milli- 

 metre wide, 0.17 long), irregularly arranged. Thyrostome arched 

 above, nearly straight below ; two small pores below it. Vibrac- 

 ular cells much larger than the zooecia, very finely punctate, 

 with a very prominent anvil-shaped articulation, inside the 

 opening, for the vibraculum. Dorsal surface ribbed, with round 

 pores. 



Localities. — Port Jackson and Port Stephens, N.S.W., and 

 Princess Charlotte Island, Queensland (T. Whitelegge). 



This is distingished by the uniformly small size and great con- 

 vexity of the zoarium, the small zooecia and by the vibracular 



