ACCOUNT OF BRITISH SPONGES. 



87 



tains a great deal of animal gluten, which in dry- 

 ing, contracts and connects the small divisions. 



Plentiful in the estuary of Kingsbridge, cover- 

 ing the stones at low water. 



13* Rigida. With obtuse, spreading irregular 

 flattish divarications, arising from the same 

 base ; usually a short stalk. 



Plate xi. fig. 1, 2. 



This sponge is as coarse in texture as Spongia 

 officinalis^ and when fresh, is of an orange co- 

 lour, which it partly retains if tolerably freed 

 from the animal gluten : the divarications are ir- 

 regular in site and shape, but usually originate 

 from one base or stem. When dried, it becomes 

 rigid, but less so when it has been exposed for 

 some time on the sea-shore, or, by repeated irriga- 

 tion, the animal gluten is decomposed and washed 

 out. 



Height, about an inch. 



What is conceived to be a small variety, has 

 the divarications more numerous and distinct, 

 spreading from a short pedicle. In this, the re- 

 ticular fibres are greatly obliterated by the large 

 quantity of gelatine retained, by the contraction 

 of which, the fibres are connected, and the sponge 

 is rendered hard and destitute of flexibiUty. 



Coast of Devon ; rare. 



f4 



