BRITISH SPONGIAD^. 203 



30. IIymeniacidon carnosa, Boiverbank. 



Halichondkia carnosa, Johnston. 



Sponge. Sessile or pedicelled, round or fig-shaped, com- 

 pact and fleshy. Surface even, minutely hispid. 

 Oscula and pores inconspicuous. Dermal membrane 

 aspiculous. Skeleton spicula spinulate, long and 

 slender. External defensive spicula same as those of 

 the skeleton ; dispersed in minute divergent groups. 

 Tension spicula sphmlate, long and slender. Gem- 

 mules spherical, membranous, aspiculous. 



Colour. Alive, buff or yellow to red-brown. 



Locality. Coasts of Ireland, Weymouth Bay, J. S. 

 Bowerbank ; Plymouth, Mr. J. H. Stewart; Durie Voe, 

 Shetland, Bantry Bay, Rev. A. M. Norman. 



Examined. In the fresh and dried states. 



The general description of this sponge by Dr. Johnston 

 is accurate, with a few exceptions. That author states that 

 " the spicula are minute, and lie principally in parallel 

 fascicles in the animal matrix/' This description of the dis- 

 position of the spicula is correct only at the immediate sur- 

 face of the sponge and for the depth of two or three times 

 the length of a spiculum ; in all the rest of the mass the 

 spicula are loosely matted together without any approach to 

 regularity of disposition. At the surface, for the brief space 

 I have mentioned, they are collected into short bundles, the 

 outer terminations of which project about half the length of 

 a spiculum in a divergent manner, so that when the 

 surface of the sponge is examined with a power 

 of 200 linear it presents a series of groups of 

 radiating spicula, which arc nearly equidistant, but 

 with no appearance of pores between them, while a 

 similar slice from the surface of llymeniacidoii saber ea ex- 

 hibits numerous pores, and the spicula projected through 

 the surface, though congregated in bundles as in IT. caniosa, 

 are not projected to so great an extent. The substance of 

 II. suberea is also more dense immediately beneath the 



