BRITISH SP0NG1AD.E. 151 



External defensive spicula attenuato-acuate or sub- 

 spiuulate, occasionally abnornio-spinulate. Interstitial 

 spicula dispersed or fasciculated ; bases and apices 

 concurrent in the fasciculi ; attenuato-spinulate, very 

 slender. 



Colour. Dried, light fawn. 



Habitat. Guernsey, Rev. A. M. Norman. 



Examined. In the dried state. 



I have seen but one specimen of this species. It coats 

 a space equal to a square of the size of about half an inch, 

 in a straggling, irregular manner, on the inside of the half 

 of an old bivalve shell. The surface is strongly hispid, by 

 the projection through the dermal membrane of the external 

 defensive spicula. The dermal membrane is so crowded 

 with the cylindro- stellate spicula, as to greatly impede the 

 view of the interior of the sponge ; these spicula are very 

 minute, and require a microscopic power of 600 or 700 

 linear to define them accurately. The ovo-spinulate spicula 

 of the fasciculi of the skeleton are very large and long, and 

 their oviform bases are large and well produced. The 

 fasciculi are very compactly formed, and the bases and 

 apices always occupy the same relative positions. The 

 fasciculi do not assume any particular direction, but are 

 irregularly dispersed amid the tissues. The basal mem- 

 brane appears to be as crowded with stellate spicula as the 

 dermal one, but the sponge is so very thin that it is diffi- 

 cult to distinguish the one from the other ; whether viewed 

 through the back or the front of the sponge, the skeleton 

 fasciculi are always beneath the stellate membrane, so that 

 no doubt can exist as to its presence. The external defen- 

 sive spicula springs from the basal membrane, and pass for 

 a great portion of their length through the dermal one, 

 radiating thence in every direction ; they are not so regular 

 in their form as those of the skeleton, and are regularly 

 attenuated from their bases to their apices. The interstitial 

 spicula appear to be dispersed to about the same extent ; 

 they are fasciculated, and are much smaller and more 

 slender than the external defensive ones. 



