58 HALF AN HOUR WITH SPONGES. 



quarters of an inch in thickness. Its colour is a 

 deep buff, and when dried it greatly resembles the 

 ordinary Turkey sponge, except that it is much finer. 

 The spicules to be obtained from this species are 

 very varying in their shapes, some being fashioned 

 like the letters S and C, others are simple needles, 

 nearly straight, and a few look like double anchors. 



Fig. 21. 



Spicules of Grantia compressa. 



Halina Bucklandi is an inconspicuous and small 

 specimen of these incrusting sponges. Its colour is 

 a greyish-black, and its size a little over an inch 

 across. You cannot well mistake it, not only on 

 account of its colour, but also from its smooth and 

 shiny appearance. Leuconia nivea is another un- 

 assuming object. Its colour, as expressed by its 



