560 



N. Annandale, 



hispid, the osciila and pores minute; subdermal space (?) small 

 (membraue mostly destroyed in the type); colour (in alcohol) dirty 

 white. Skeleton feebly coherent, with small irregulär, triangulär 

 meshes outlined for the most part bj' single spicules, with mere 

 traces of fasciculation, Skeletons spicules (megascleres) numerous 

 but not sufficiently so to make the sponge hard, smooth or slightly 

 rough, sharply pointed, nearly straight, short, slender, about 24 times 



Fig. A. 



Spicules of S. amhigua. 

 a Skeletou spicules. b Gemmule spicules. c Free microscleres. 



as long as their greatest diameter (in the type specimens). Free 

 microscleres sparsely scattered in the parenchyma, fairly numerous 

 in the membrane, resembling gemmule spicules but smaller and 

 rather finer. Gemmules small, subspherical, flattened at the base, 

 by which they are firmly adherent to the support of the sponge, 

 grouped together so as to form a pavement layer, each provided, 

 immediately outside the chitinous coat, with a sparse layer of 

 microscleres lying nearly parallel to it. outside this layer with a 

 thick coat of relatively large, polygonal air-chambers arranged in 

 several tiers, and outside this coat with a second layer of micro- 

 scleres resembling the inner one; the single aperture terminal, pro- 

 vided with a broad, straight, vertical, cylindrical chitinous tube, 

 which is patent above, does not project or projects very little 

 beyond the air-chambers and is contracted at its base, its distal 

 extremity being devoid of a thickened rini; the diameter of the 

 gemmule very variable. Gemmule spicules straight or nearly so. 



