ESSAY ON SPONGES. 77 



I shall now proceed to give a description of the 

 several species of sponges that have been discover- 

 ed to inhabit the British Islands. 



so small a body. It appears to me, that this substance is in 

 fact the nidus of some aquatic insect, which may possibly con- 

 gregate to deposite their eggs ; and that the fibres, or threads 

 that decussate each other, are attached to the ova for their secu- 

 irity in mass, as we perceive in those of some spiders and other 

 land insects. 



SPONGIA 



