Sponges from the Atlantic Ocean. 231 



tation, which is only observed in the dry specimens, indicates 

 that, as usual, the accumulation of the foreign objects is 

 contined to the lines of the subjacent, in this instance sub- 

 corneous, dermal reticulated structure. 



On the 29th March last the Eev. A. M. Norman sent me 

 another species of this genus, for which he proposes the 

 specific name of " incritstansy It only differs from that 

 above described in the papillae of the surface not being so 

 prominent and thorny, and in its structure being areolar and 

 sandy througliout like that of Drjsidea fragiUs, and of 

 a light yellow instead of a pink cream-colour when dry. 

 Loc. " Shetland, 170 fathoms,^' on hard objects. 



Spongia officinalis. (PI. XII. fig. 1, d.) 



General form unequally lobate, spreading, sessile. Colour 

 light brown. Surface irregularly lobed and minutely divided 

 into polygonal spaces by the dermal horny reticulation, which 

 supports and thus shows itself through the transparent dermal 

 sarcode, projecting from the latter at the knots or points of 

 union of the lines respectively in attenuated, minute, horny 

 filaments, which give the surface a hairy appearance. Pores 

 in the interstices of the dermal reticulation. Vents large and 

 irregular both in size and situation. Internally consisting of 

 a densely reticulate, anastomosing, horny, transparent, tough, 

 brownish fibre, which gives the brown colour to the sponge ; 

 supporting transparent areolar sarcode, which is traversed by 

 the excretory canal-system, often running in a branched form 

 for some distance just below the dermal sarcode before opening 

 at the vents mentioned. Size Ij inch in its largest diameter. 



Hah. Marine, on hard objects. 



Loc. Same as that of Aplysina ncevus^ viz. station 65. 



Obs. This, which is a genuine specimen, although small, of 

 Spongia officinalis, is only found in the jar numbered 65, 

 where it has partly overgrown the upper valve of the same 

 Terebratule as that on which Aplysina ncevus has spread 

 itself (fig. 1, d), presenting between them a small portion of 

 Dysidea fragilis (fig. 1, e). 



While the Terebratule bears the three sponges just men- 

 tioned, it is itself fixed to a pebble (fig. 1, a) which bears 

 in addition two small specimens oiPhakelUa infundibvliformis, 

 Johnst. (fig. ^ifff)-, also the basal fragment of a cylindrical 

 calcareous worm-tube over which Latrunculia cratera, Bocage, 

 has grown (fig. 1 , gg) , and at the foot of this on the pebble 

 a little patch of Microciona longispiculum, n. sp. (fig. 1, A); so 

 that the pebble and the Terebratule together bear six species 



16* 



