CHALINOPSILLA. 113 



uniformly scattered over it ; where the surface is undulating the oscuia are 

 situated on the prominent parts o£ it. The sponge is greyish brown in spirit ; 

 in the dry state pretty soft, compressible, but not elastic. 



The mrface-skeUton consists of a regular network of bands of foreign bodies, 

 which are 0-3 millim. broad ; the polygonal meshes between them have a 

 similar width. The supporting-skeleton consists of knotty longitudinal main 

 fibres 0-5 miUim. thick, and, on an average, 1-5 millim. distant ; these are 

 filled with foreign bodies, the clear spongin layer around them is only 0-05 

 miUim. thick. No spicules have been observed in the connecting-fibres, which 

 are, on an average, 0-05 millim. thick, and mostly unbranched. 



Geogeaphical Distribution. — South coast of Australia : Bass Straits : o£E 

 East Monceour Island (' Challenger '). 



Chaliuopsilla impar, Carter. 



Dactylia impnr, H. J. Carter, "Descriptions of Sponges from the Neighbour- 

 hood of Port Phillip Heads, South Australia," Annals and Magazine of 

 Natural History, ser. 5, vol. xv. p. 309 (1885). 



The sponge consists of a number of branches, which grow up from a 

 common centre. All these branches lie in one plane, and are laterally com- 

 pressed in the same direction as the whole sponge; they coalesce in their 

 proximal half to form a continuous plate, from the margin of which the 

 distal, free portions of the branches project. The central lamella is irregular ; 

 the ends of the branches are all parallel and upright, and rounded at their 

 distal ends. The whole sponge attains a breadth of 130 millim., a height 

 of 120 millim., and a tliickuess of 6 millim. The free distal portions of the 

 branches are somewhat irregular in shape, from 5-12 millim. broad, but 

 never more than 6 millim. thick. The surface is uneven, undulating. The 

 highly prominent oscuia are arranged m longitudinal rows, which extend along 

 the narrow margin of the branches, and centripetally from these in radial rows 

 over the central lamellar part of the sponge ; they are, on an average, 

 1-5 millim. wide, and project sometimes as much as 4 millim. over the surface. 

 The sponge is very hard and scarcely compressible. The colour of the dry 

 skeleton is orange-yellow. 



The surface-sl-eleton consists of a network of fibres, composed of sand- 

 grains of various size. The fibres are 0-2 millim. thick, and the irregular 

 meshes between them 0-4 millim. wide. The sand-grains vary in size from 

 0-1-0-2 millim. The inhalant pores are situated in the membraiies, which 

 are expanded in the meshes ,; between them abundant scattered sand- 

 grains, similar to those constituting the fibres of the surface- skeleton, are 

 found. The suj^porting-sJceleton consists of slightly uneven main fibres, which 



I 



