16 A MONOGRAPH OP THE AUSTRALIAN SPONGES, 



surface is perfectly smooth. The colour is subject to similar 

 variations as in some European species and varies from light dull 

 yellowish gray to dark bluish black. 



Mostly the side exposed to the light seems to be of a darker 

 colour than the other. However a strict rule can be established 

 here as little as in the case of Chondrosia reniformis (1). 



The outer surface-colour only is subject to the above variations. 

 The interior of the Sponge always has the same dull grey colour. 

 A Cortex is not distinguishable. 



The oscula are raised slightly over the surrounding surface 3 — 6 

 in number, always on the upper side of the flat specimens, circular 

 and about 2 — 3 mm. in diameter. 



The bulbous specimens have only one osculura. 



The outer part of the Sponge appears very dark and intrans- 

 parent, in consequence of the great number of pigment granules 

 in the dark parts. The light parts are much better suited for 

 investigation and more transparent. This outermost zone always 

 appears radially striped in consequence of the inhalent canals all 

 standing vertical on the surface in their outer portion. 

 Structure. 



Our species does not seem to differ from Chondrilla nucula (2) 

 in any respect, except the shape of the spicules. There are two 

 kinds of spicules. (Figs. 11, 12.) 



Both kinds are met with not very abundantly throughout the 

 Sponge. Towards the outer surface, and particularly also in the 

 canal walls, they became much more numerous. 



The larger kind measure 0*064 mm., the smaller kind 0-012 mm. 

 across. The spines of the larger kind are about 0*006 mm. long 

 at 0-004 mm. broad. The spines of the smaller kind measure 

 0-003 X 0-001 mm. 



The larger kind represents a ball with distant short and truncate 

 smooth spines which are rounded terminally. The surface of the 

 central sphere is clearly visible between the spines. In the small 

 kind the spines are pointed and relatively much longer, three 



{I) F. E. Schuhe. Die Spongieii des Adriatisclien Meeres. Seite 97-98. 

 (2) F. E. Schuhe. Die Familie der Chondrosidae. Zeitschrift fiir 

 wissenschaftliche Zoologie. Band XXIX., Seite 108 ff. 



