SPONGES FROM THE HERGUI ARCHIPELAGO. 



77 



becoming so large and the species so different, that it will soon be 

 questionable whether they should all be included in a separate 

 family, or relegated respectively to the groups to which they may 

 belong. Suberites coronarius as well as the following species, 

 viz. Amorphinopsis excava?is, are instances of the great differences 

 between some species included in this group. 



Amorphinopsis excavans, n. gen. et sp. (Plate V. figs. 12- 

 15.) 



Laminar, continuous, very thin, spreading horizontally over a 

 piece of old coral, which it has excavated vertically. Consistence 

 soft. Colour pinkish, almost white. Surface even, following 

 that of the object on which it may be growing, presenting a 

 beautiful arrangement of the spiculation on the surface, which 

 gives it the appearance of a fabric formed of little stars. Pores 

 and vents not seen. Spicules of two forms, viz. : — 1, skeletal, 

 acerate, fusiform, slightly curved, smooth, and very gradually 

 sharp-pointed, varying much in size, 50 by 2|-lS00ths inch in 

 its greatest dimensions ; 2, acuate, slightly curved, slightly fusi- 

 form, smooth and sharp-pointed, head obtuse, not inflated, less 

 in diameter than the shaft, varying in size under 10 by -£-1800th 

 inch in its greatest dimensions. Horizontal diameter of speci- 

 men about 3 inches ; the portion which lies in the excavations 

 about \ an inch in vertical diameter. 



Sab. Growing over and incrusting and penetrating old coral. 



JLoc. King Island. 



Obs. At first this sponge, from its structure and white colour, 

 looks very much like Halicliondria panicea, J ohiist., = Amorphi?ia, 

 Schmidt ; but it differs from it in its horizontal laminar growth 

 and the presence of an acuate flesh-spicule in addition to the 

 large acerate, together with the excavating habit, in which it 

 approaches the Suberites ; so that having regard to these resem- 

 blances to such totally different sponges, I have considered it 

 desirable to call it after neither, and so have given it the generic 

 name Amorphinopsis. No laminar sponge with this spiculation 

 aud excavating habit has, I think, hitherto been described. 



DoNATIA LTNCTJRITJM, auct. 



But for the colour being whitish, grey, or leaden white, instead 

 of orange, this sponge, of which there are two specimens, would 



LINN. JOURN. — ZOOLOGY, VOL. XXI. 7 



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