146 A MONOGRAPH OF THE 



Colour. Cream white. 



Locality. Western coast of Ireland ; 100 fathoms. 

 Captain Hoskins. 



Examined. Preserved in spirit. 



This interesting species was brought up from a depth of 

 100 fathoms, by the sounding line, by the officers of 

 H. M. ship Porcupine, and was sent to me for examina- 

 tion by my friend, Professor Wm. King, of Queen's College, 

 Galvvay. It is in three pieces, neither of which exceeds 

 half an inch in length and about two lines in thickness. 

 The surface has a very peculiar appearance, being studded 

 at irregular intervals with conical projections, which are 

 produced by the distal terminations of the skeleton fasciculi 

 pressing against the inner surface of the dermal membrane, 

 and thus projecting it above the general surface of the 

 sponge. The skeleton of this species differs from other 

 British Hymeraphias in having the primary skeleton spicula 

 each surrounded by a fasciculus of secondary skeleton spi- 

 cula, serving to strengthen and extend the lines of the 

 skeleton. These spicula are closely clustered around the 

 primary ones ; they are large and long, and attenuate 

 gradually from the inflation at the middle to each termi- 

 nation, which presents a singular bifid appearance. The 

 spicula of the dermal and interstitial membranes are also 

 very remarkable, as they are the only verticellately spined 

 spicula that are yet known to occur in a British sponge; 

 the other two instances of the existence of verticellately 

 spined spicula being in West Indian species, and in both 

 these cases they are internal defensive organs, while in this 

 sponge they are decidedly tension spicula. In the young 

 state these spicula occasionally appear to be moniliform, 

 and without spination, but this variation in form appears 

 to arise from incomplete development. 



4. Hymeraphia stellifera, Boivcrbank. 



Sponge. Coating, exceedingly thin. Surface even, strongly 



