GRANTIA. 175 



Hab. On the sides of rocks and on sea-weeds near low 

 water-mark. Bressay Sound, Shetland, Jameson. At Daw- 

 lish in Devonshire, Montagu. Near Tynemouth, not very 

 plentiful, Miss Forster. From the circumstance of its having 

 escaped the notice of Ellis, this species may possibly be rare on 

 om- southern coasts, but it grows in abimdance on those of 

 Scotland, G. J. Found not uncommonly in Ireland, accord- 

 ing to Mr Templeton, and I have seen many specimens from 

 various localities. 



Sponge pendant by a narrow base, sometimes 1^ inch in 

 height, and 2 inches in extreme breadth, usually about half 

 this size, oval or somewhat triangular or pentagonal, greatly 

 compressed, of a straw colour, becoming grejish in drying, the 

 texture close, the outer surface even and smooth, closely punc- 

 tured, the inner reticulated with larger pores. It is hollow, and 

 has at the top of small specimens, and at every projecting 

 angle of larger ones, a circular vent of considerable size with a 

 plain rim. When left uncovered by the retreat of the tide the 

 sides of the sponge are in contact, and the individuals hang 

 like small white leaves from the surface of the rocks ; " but, 

 when suspended for a short time in pure sea water, their pa- 

 rietes separate, and they become like small distended bags pour- 

 ing forth a continued and obvious current." Grant. — " The 

 external surface is crowded with numerous spicula, thick and 

 bent at one end, tapering to the other ; the pores on the inner 

 surface are larger, and the spicula triradiated ; besides these 

 two well-marked forms of spicula, there are other linear, point- 

 ed, and of unequal lengths." Fleming. 



Spongia compressa and *S'. foliacea of Esper have neither 

 of them any relationship to Grantia compressa. 



The Spongia urceolus oi MuUer, Zool. Dan. iv. 42, tab. 

 137, fig. 3, is probably a variety of the species with a single 

 terminal aperture. 



