396 



Miss I. B. J. Sollas on the Inclusion. 



The proper skeleton consists of not very numerous oxeas 

 measuring '96 x '016 mm., and arranged partly in loose 

 strands, partly irregularly. The strands run up to the 

 surface and their free ends project. This spicular skeleton is 

 su])plemented by sand-grains scattered through the tissues 

 and quite unconnected with one another. Most of them have 

 a covering of some brown substance. 



Fig. 1. 



a and b. Portions of the surface of Migas j^orphyrion^ showing the 

 inclusion cf sand-grains by pseudopodia-like extensions of the surface- 

 tissue. 



Fig. 2. 



Portion of the surface of Migas porphyrion, showing a sand-grain 

 seated on a pillar of cortical tissue. 



The incorporation of foreign bodies occurs commonly 

 among Ceratosa, and in the Monaxonida it is found in the 

 Gelliodine genera Phoriospongia and Sigmatella, in the 



