BRITISH SPONGIADyE. 121 



Colour. — Ochreoas yellow, when dried. 

 Habitat. — Shetland, Mr. Peach. 

 Examined. — In the dried state. 



This sponge was dredged at Shetland, in 1864, by Mr. 

 J. Gwyn Jeffreys, and preserved for me by my friend Mr. 

 Peach, who accompanied the expedition. It is the only 

 specimen I have seen of the species. It is three inches in 

 height, the same in breadth, and does not exceed four lines 

 in thickness near the base, and gradually becoming thinner 

 towards the distal extremity, where the margin is quite 

 thin and sharp. The dermal membrane is to a great 

 extent destroyed, but where it remains in situ it appears as 

 if the surface had been smooth and even. In its present 

 dried state it is slightly hispid, by the projection of the 

 spicula of the distal extremities of the secondary ramuli of 

 the skeleton. The dermal membrane has no proper spicula 

 of its own, but in parts it is furnished with large acerate and 

 acuate flexuous tension spicula, of the same description as 

 those which occur so abundantly in the interstitial membranes. 

 The distal spicula of the secondary ramuli frequently 

 diverge at their apices, approximating to form an external 

 surface to the sponge, and it appears that it is where this 

 divergence does not take place to the necessary extent that 

 the dermal membrane is furnished with the large tension 

 spicula as described above. 



The axial columns of the primary radial fasciculi of the 

 skeleton are very thin, the great size and strength of the 

 spicula of which they are composed compensating for the 

 want of numbers, and both this portion of the skeleton and 

 the secondary ramuli are formed of spicula of a size greatly 

 exceeding those of the corresponding parts in P. ventila- 

 brum. The spicula of the secondary ramuli, although quite 

 as stout, are not more than about half the length of those 

 of the primary ramuli of the skeleton. The interstitial 

 spaces are very large, and their membranes are abundantly 

 fm-nished with remarkably large and strong flexuous tension 

 spicula, which frequently have their terminations imbedded 

 in different secondary ramuli; they cross each other at 



