BRITISH SPONGIAD^. 107 



spioula, without spines, and with a considerable number 

 of dispersed minute angulated dentato-palmate, anchorate, 

 retentive spicula, which are generally attached by the 

 middle of the back of the bow of the spiculum to the 

 inner surface of the membrane. In one small portion of ' 

 the dermal membrane the anchorate spicula were arranged 

 in a circular group, one end of each spiculum being inserted 

 in the inner surface of the membrane, and the remainder of 

 the spiculum being projected from its plane at about an 

 angle of 45°j the whole forming a beautiful rosette-shaped 

 group, similar in appearance to the grouping of the like 

 description of spicula in Hymeniacidonlingua ; but although 

 I examined many other small portions of the dermal mem- 

 brane of the same specimen, I did not meet with a second 

 case of the same mode of arrangement. 



It is the first time that I have met with this singular form 

 of spiculum, in which the bend of each of the hooks appears 

 as if each side of the hook had been forcibly compressed 

 towards the other, so as to form an angulated hook instead 

 of a regularly curved one. The skeleton is rather slender, 

 and is composed of closely packed acuate spined, and acerate 

 unspined spicula, the latter being the same as those of the 

 dermal membrane, but the defensive spicula of the skeleton 

 ■consists of entirely spined acuate spicula, the bases being 

 inserted about once or twice the length of the diameter of 

 the spiculum in the membrane, and the rest of the spiculum 

 projecting at or very near to right angles. The interstitial 

 membranes are abundantly but irregularly furnished with 

 the three descriptions of spicula, and are very frequently 

 armed with the spined acuate spicula, in the same manner 

 as the skeleton ; among the spined spicula are many which 

 are shorter and more attenuated than the others, and these 

 appear to be truly the defensive spicula, but in this curious 

 species both the large and the small acuate, spined spicula 

 are projected indifferently and in great profusion from all 

 parts of the membranes. 



The third specimen sent me by Mrs. Griffiths was labelled 

 " Scarlet Poetid Sponge." I presume, therefore, that in its 

 living state, that is, its natural colour, it is found, according 



