BRITISH SPONGIAUyB. 183 



SI.Hymeniacidon armatura, Bowerbank. 



Sponge. Coating, thin ; surface smooth. Oscula simple, 

 dispersed, minute. Pores inconspicuous. Dermal 

 membrane pellucid, abundantly spiculous ; spicula 

 cylindrical, sometimes sub-clavate, dispersed or loosely 

 fasciculated. Skeleton. Spicula acuate, stout. Inter- 

 stitial membranes ; tension spicula numerous, same as 

 those of dermal membrane. Internal defensive spicula 

 acuate, entirely spined, few in number. 



Colour. Dried, dark red brown. 



Habitat. Strangford Lough, Professor Dickie. 



Examined. In the dried state. 



I received this sponge from Professor Dickie, of Queen's 

 College, Belfast. It covers nearly the whole of the valve of a 

 small Pecten, rather less than an inch and a half in width, and 

 in its dried state it does not exceed a line in thickness. There 

 are a few small oscula near the margin of the sponge, visible by 

 the assistance of a lens of two inches* focus, but I could not de- 

 teet a single pore open. The dermal membrane is crowded 

 with tension spicula, irregularly dispersed on its surface, and 

 sometimes loosely fasciculated, and they appear to be equally 

 abundant in the interstitial membranes. When fully deve- 

 loped, these spicula are sometimes slightly dilated at their 

 terminations. They are nearly as long as the acuate ske- 

 leton spicula, but only about half their diameter. The 

 internal defensive spicula are sparingly dispersed over the 

 inner surface of the dermal membrane and on the interstitial 

 one's, and were mostly in a recumbent position ; they are 

 small, and require a power of about 400 linear to exhibit 

 them well, and without immersion in Canada balsam they 

 are not to be detected in situ. 



