6.2 DK. G. J. HINDE ON CALCTSPONGES [Peb. I9OO, 



Bactbonella australis, sp. nov. (PI. Y, figs. 12-19.) 



Sponges small, of various forms, club-shaped, conical, rounded or 

 hemispherical, either supported on a short pedicel, sessile with 

 flattened bases, or deeply concave. A small specimen is 5 mm. in 

 height by 5 mm. in width, the largest 13*5 mm. by 10 mm. in 

 width. The body of the sponges is frequently hollowed out by 

 tubes and chambers, probably due to some boring organism. The 

 sponges are now infilled with calcite, and their spicular structure 

 is very imperfectly preserved. 



The entire surface of the sponges is covered with a smooth, thin 

 dermal layer, which conceals the apertures of the radial canals, but 

 the spicular structure cannot be recognized. A vertical section 

 shows radial lines extending from the basal to the outer surface of 

 the sponge ; these lines are from 0*08 mm. to Ol mm. apart, and 

 they appear to be mainly formed of relatively stout apical rays of 

 spicules arranged so as to overlap each other. The rays are straight, 

 elongate-conical, from 0*2 to 0'35 mm. in length and about 

 0-08 mm. in thickness at the base (PI. IY, fig. 19). The facial rays 

 of these spicules can be seldom distinguished in sections. The 

 lines of the apical rays are connected by numerous transverse 

 bars : probably they represent small spicules of the same character 

 as in the preceding species. No indications of detached spicules 

 have been preserved. The surface beneath the dermal layer shows 

 the minute rounded apertures of the radial canals, about O09 mm. 

 in width ; they are bounded by the facial rays of spicules fused at 

 their points of contact with each other (PI. IY, fig. 18). The apical 

 rays of the spicules near the exterior do not seem to penetrate the 

 dermal layer. 



This species differs from Bactronella parvula, in its habit of growth, 

 the complete covering of dermal layer, and the larger size of the 

 spicular rays. No comparison in other structural details is possible, 

 on account of the imperfect preservation of the specimens. 



Distribution. — Not uncommon in a limestone-rock mainly com- 

 posed of fragments of polyzoa with echinoid-tests and brachiopoda, 

 shown in a small cliff-section at Flinders (Yictoria). The beds overlie 

 the ' Older Yolcanic ' and are regarded as of Eocene age. Collected 

 by Mr. T. S. Hall, M.A. 



Teetocalia 1 pezica, gen. et sp. nov. (PI. IY, figs. 20-29.) 



Sponges of small size, simple, cup-shaped, subcylindrical or 

 rounded, with a cup- or funnel-shaped cloaca, their bases flattened or 

 variously curved, and concave where the sponge has been attached 

 to foreign bodies. Rarely is a dermal layer preserved; where 

 present it is restricted to the base and to a narrow band round the 

 side. The rest of the surface exhibits numerous rounded canal- 

 apertures and minute irregular mesh-interspaces. The sponge-wall 

 s moderately thick, the summit convex, with well-defined margins 



1 TptjTos, pierced through ; icaXid, a birds-nest. 



