HTMBNIACIDON. 87 



" Habitat. — "WestportBay, Co. Mayo, Ireland, at low 

 tides ; Rev. A. M. Norman. 



" Examined. — In the dried state. 



" I received two small specimens of tliis sponge for 

 examination from my friend the Rev. A. M. Norman. 

 The largest of the two did not exceed an inch in length 

 by half an inch in breadth, and the smallest one was half 

 an inch in diameter. On neither of them was there 

 any mark of having been attached to any base ; the 

 appearance of the surface in both was that of dirty, 

 . slightly corrugated kid-glove leather of a fawn-yellow 

 colour, and to the unassisted eye the surface appeared 

 smooth, but minutely wrinkled. When a section of 

 the sponge at right angles to its surface mounted in 

 Canada balsam is viewed beneath the microscope, the 

 aspect is very different ; the surface is then seen 

 bristhng with a dense stratum of acuate spicula 

 disposed at about right angles to the surface. When 

 a small portion of the dermis is submitted to examina- 

 tion in Canada balsam with a power of 100 linear, it is 

 seen to be furnished with a coarsely formed dermal 

 network, the rete of which has almost as great a 

 diameter as that of the areas of the network, and from 

 the outer surface of this reticulate structure the 

 abundant crop of external defensive spicula are pro- 

 jected ; these spicula and those of the network are all of 

 the same form and size, as nearly as possible, and purely 

 acuate. 



" The skeleton does not present any especial specific 

 characters; it is abundantly supplied with acuate 

 spicula, very similar in size and form to those of the 

 dermis, and no other form of spiculum is found in the 

 structures of this sponge ; but it is satisfactory that 



