Art. X. — Two new Victorian Palceozoic Sponges. 



By T. S. hall, M.A. 



(Demonstrator and Assistant-Lecturer in Bioloo;y in the University 

 of Melbourne). 



[Bead 8th September, 1898.] 



(With Plate XIV.). 



Protospongia oblonga, n.sp. (PL XIV., Figs. 1-3. 



Sponge vasiform ; width about 4 cm.; height of the imperfect 

 specimen about 5 cm., tapering roundly towards the base. 

 Spicular meshwork with oblong interspaces. Spaces between 

 the primary spicules about 3 mm. broad and 4 mm. long. 

 Primary and secondary spicules present, but apparently none of 

 a higher order. Flesh spicules closely covering the interspaces, 

 their true shape and arrangement being uncertain, some appearing 

 merely as short straight rods and others as small crosses. 



The skeleton is pyritized and preserved in a hard black shale, 

 which adheres in a thin film bo the surface of the spicules so that 

 they show as fine raised lines, or where removed, as distinct 

 grooves. The ends of the primary spicules are seen to overlap 

 in a few instances, and occasionally separation has taken place 

 along the oblique line of junction, thus showing the essential 

 Lyssakine nature of the sponge. The pyritous replacement of 

 the spicules has occasionally been dissolved, either wholly or 

 partly, leaving a hollow cast, and one such cast shows a canal 

 running down perpendicularly to the plane on which the sponge 

 lies, thus clearly demonstrating the presence of a fifth ray. Dr. 

 G. J. Hinde^ points out the natural difiiculty which exists in 

 detecting a fifth ray if it were present, and speaking of the 

 Quebec Hexactinellidse generally, says that judging by the 

 analogy of allied recent forms it is probable that, in most cases, 

 these spicules were furnished with a fifth ray at right angles to 

 the other four. Both before and after this date, however, he 



1 Proc. and Trans. Roy. Soc, Canada, vol. vii., 1890, sec. iv., p. 36. 



