38 Proceedings of the Royal Society of Victoria. 



The sponge is stipitate, thin, flabellate. The main skeleton 

 consists of a faii'ly regular, rather small-meshed, sub-rectangular 

 network of strongly-developed horny fibre, cored and echinated 

 by smooth, short, stout styli or subtylostyli of variable size. This 

 skeleton is condensed in the central plane. There are also 

 present long and very slender, smooth tylostyli, with well-developed 

 heads. These appear to be very characteristic, they occur in 

 longitudinal whisps and scattei'ed towards the middle of the 

 sponge, and in loose radiating tufts at the surface. No micros- 

 cleres have been detected. The species is interesting because it 

 shows a structui'e intermediate between the Ectyonincz and 

 Axifie/iidce, so that it might, with almost equal justice, be placed 

 in either group. Indeed, I find from examination of the British 

 Museum specimens that Mr. Carter's Echinoclathria tenuis and 

 Piiakellia papyracea are identical. 



R.N. 287 (18 f; "bright brick red "); 353 (19 f; "Venetian 

 red with yellow spots"); 1075 (x A). 



B.M. sp. 43 (y''- Ecliinoclatliria tenuis, C. type," Reg. 86-12-15- 

 147); d. 88 {'' PiiaJ^ellia papyracea;' Reg. 86-12-15-231). 



Opiilitaspongia gat>rieli, n. sp. 



Sessile, spreading, encrusting ; rising into short mammiform 

 projections, each bearing a smallish vent. Surface uneven, with 

 minutely reticulate dei'mal membrane in the depressed portions, 

 moi'e or less granular elsewhere. Texture soft, resilient ; colour 

 in spirit pale yellow. 



SJicleton, the main skeleton is a sub-rectangularly meshed 

 network of strongly-developed horny fibre. The primary fibres 

 are about 0"055 mm., thick and sparsely cored with slender 

 styli. The secondary connecting fibres ai'e a little slenderer and 

 without any spicular core. The dermal skeleton consists of 

 sparse tufts of slender styli projecting very slightly Ijeyond the 

 dermal membrane. 



Afegascieres, smooth, straight styli, of two chief sizes, {a) 

 comparatively short ; hastately and very sharply-pointed at the 

 apex, and evenly rounded off" at the base ; measuring about 0*09 

 by 0-0042 mm. These occur pretty abundantly scattered in the 

 soft tissues between the fibres ; a very few of them echinate 



