SPOXGES FROM THE MERGE I ARCHIPELAGO. 



65 



Sab. Growing over hard objects, e. g. the slender sterns of 

 G-orgonicB, or convex bodies, or over the shell-detritus of the sea- 

 bottom. 



Loc. Muddy flats, King Island. 



Obs. The fragility of this genus is due to the delicacy and 

 scantiness of the sarcode, rendering it peculiarly brittle, and there 

 is a want of toughness consequent on the preponderance of the 

 " foreign objects " over the keratode throughout the fibre. At 

 the same time, this fragility becomes considerably increased when 

 the specimen has been torn from its place of growth by the 

 waves, and finally thrown up " high and dry " upon the beach ; 

 under this condition it received the name " Dysidea''' from Dr. 

 Johnston, who, had he seen it growing in its natural habitat, 

 would have proposed for it a very different appellation, While 

 the British species is massive and lobate, this presents, as above 

 stated, a columnar structure, in which the columns are more or 

 less subdivided or branched, and the reticulate fibre of which 

 they are composed terminated by short spines, which gives the 

 whole mass an appearance like that of a prickly plant or 

 shrub — e. g. JJlex. This species is also found at Mauritius. 



Dysidea ramoglomerata, var. ramottjbulata, nov. 



The same as the foregoing, but with the branches tubular. 

 Size of specimen about 3 inches in its longest diameter and 1 inch 

 thick, mixed with shell-detritus at the base. 



Dysidea ramoglomerata, var. graxtjlata, Carter. 



Massive, sessile, spreading, composed of erect columns in juxta- 

 position, branched and uniting with each other; intermingled 

 with shell-detritus at the base. Consistence fragile. Colour 

 dark brown. Surface of sponge as a whole even, horizontal, and 

 uninterruptedly roughened, with the exception of certain round 

 holes and of the depressions between the heads of the segments. 

 Yents represented by the " round holes " just mentioned, which 

 occur on the more prominent ends of the branches and in the 

 midst of the roughnesses of the surface. Granulations consisting 

 of little, subspherical masses of foreign bodies, which usually 

 replace the spinous terminations (conuli) on the surface of these 

 sponges. Size of specimen about 7 inches in its longest diameter 

 and 1| inch thick. 



