112 CHALINOPSILLA. 



The sponge appears as an irregular, partly repent and partly erect branching 

 structure ; the branches grow out from one point and ramify in an irregular 

 manner ; they are irregularly curved and not parallel to each other. The 

 whole sponge attains a length of 250 millim., and the branches are, on an 

 average, 8 millim. thick. The surface is very uneven, so that the branches 

 attain a knotty appearance. The oscula are situated in regular longitu- 

 dinal rows ; they are circular and small, less than 1 millim. wide, and do not 

 project over the surface. The sponge is very hard and incompressible. The 

 colour of the living sponge is light yellow. 



The surface-skeleton consists of a simple network of fibres, 0*1 millim. 

 thick, which are entirely composed of foreign bodies ; the meshes between 

 them are, on an average, 1'5 millim. wide. The foreign bodies are small 

 sand-grains, with an average diameter of 0'05 millim. 



The sujyporting-sTceleton consists of knotty parallel main fibres, 0*6 millim. 

 thick and 1*4 millim. distant, which contain large scattered sand-grains, with 

 an average diameter of 0*25 millim. ; these are about 0*13 millim. apart. The 

 connecting-fibres usually have two roots, but are otherwise hardly at all 

 branched ; they generally contain an axial series of siliceous spicules, which 

 appear longitudinally situated; these spicules are oxea, 0*07 millim. long and 

 0*006 millim. thick, intact or more or less fragmentary. 



Geographical Distribution. — Mauritius (Canterbury Museum). 



North coast of Australia : Torres Straits {Macleay). South coast of Aus- 

 tralia : Port Phillip Heads, V. ( Wilson). East coast of Australia : Queensland 

 (Ramsay). 



Chalinopsilla arborea, var. ramosa, Marshall. 



Psammoclema ramosum, W. JNIarshall, " Untersuchungen iiber Dysideiden und 



Phoriospongien," Zeitschrift fiir wissenschaftliche Zoologie, Band xxxv. 



Seite 190 (1880). 

 Psammoclema ramosum, N. de Polejaeff, " Eeport on the Keratosa," Eeports on 



the Scientific Eesults of the Voyage of H.M.S. 'Challenger,' part xxxi. 



p. 43 (1884). 



Irregularly branched cylindrical sponges, apparently more or less repent, and 

 attached at several points along the side. The digitate branches are rounded at 

 the ends ; they do not form anastomoses ; the central one is generally thicker, and 

 appears as a stem. The sponge attains a length of 200 millim. ; the branches are, 

 on an average, 8 millim. thick, whilst the stem, the surface of which is not nearly 

 so even as that of the branches, attains a thickness at some places of 20 millim. 

 and more. The surface is quite smooth ; the oscula are about 2-5 millim. wide and 



