l'2(i BRITISH SPONGES: 



Hab. (a. J Dredged in eighteen fathoms water in the mid- 

 dle of Butribuy bay, near Roundstone : it occurred in abun- 

 dance, Wm. 3PColla. (3.) In perforations of the shell of the 

 oyster, (Ostrea edulis) : abundantly in the oyster beds at Pres- 

 tonpans, off Inchkeith, and in the roads of the Firth of Forth, 

 Grant. Plymouth harbour, J. C. Bellamy. 



This sponge, without beauty or definite form, occurs in hard 

 earthy masses from two to four inches in diameter and an inch 

 in thickness, when dried of a dirty brown colour, hard and in- 

 compressible, with an irregular uneven surface. The interior is 

 yellow, imperfectly cellular, friable and stuffed wdth shells, the 

 tubes of testaceous worms and gravel. The mass is drilled with 

 short canals which open without order on the surface in the form 

 of circular holes, having more the appearance of perforations 

 made by wontns than of the ordinary oscula. These are some- 

 times open and empty, but more commonly they are filled with 

 a spongy mass that plugs up the aperture, forming a small ob- 

 tuse papilla in it. From the worm-eaten appearance of the 

 sponge one is tempted to believe that Montagu may have had 

 specimens of it in view when he drew up the description of his 

 Spongia fava ; and specimens of the two species are sometimes 

 much alike. Our most perfect specimens were sent from Ire- 

 land by Mr Wm. M'Colla, who says that in a fresh state it is of 

 a yellow colour, and that the perforations were then raised tu- 

 bercles. He adds, that the species seems to be very destruc- 

 tive to the shells that come within its reach ; and in several in- 

 stances he had found large specimens of the Pecten opercularis 

 killed by the encroachments of this parasite. 



Having sent some morsels of a specimen to Mr Bowerbank, 

 he favoured me with the figures of the spicula from which our 

 woodcut has been made. " The rounded terminations or bases," 

 he observes, " are very singular, the thick part not being quite 

 at the end in all cases. The hollow in the bulb is not alwavs 



