CORALS AND CORAL-ANIMALS. 



153 



more or less completely encrusted by Zoanthoid polj'ps, that may attain to a height of fifteen or 

 eighteen inches. Divested of the polyps by which it is constructed, this central axis is found to 

 consist of a hollow core of thin, non-spiculiferous, papier- 

 mache or leather-like material, averaging about half-an- 

 inch in diameter, and having usually a more or less 

 distinctly zigzag habit of growth. On examining a per- 

 fect polj'par}', the polyps are found to be clustered most 

 thickly on the projecting outgrowths of the axial angles, 

 the intervals between them being chiefly occupied by the 

 fleshy substance. In the living state, moreover, these 

 intermediate areas are commonly covered with minute 

 algae, zoophytes, and other marine growths that consider- 

 ably mask its true nature. The adult polyps in this type 

 expand to a diameter of about one inch ; but they exhibit 

 their most attractive colouring in their contracted, or 

 semi-expanded state, it being only under such conditions 

 that the brilliant emerald-green annular ring is visible, 

 which lies sphincter-like around the tentacular wreath. 

 The remainder of the body is usually a didler green in- 

 clining to pink, speckled with red-brown. The tentacles 

 are usually a rich chocolate-brown, but sometimes some- 

 what purplish ; the centre of the oral disk is a dull orange, 

 spotted with red-brown, after the manner of the external 

 body-surface The species now described is somewhat 

 widely distributed, it having been collected by the author 

 on the Barrier Reef from Torres Strait to opposite Mackay, 

 and also at Port Darwin and Cambridge Gulf, on the 

 North Australian coast-line. In all instances, the species 

 was found growing, in a perpendicular position, on some- 

 what muddy foreshores, and it was exposed to view at 

 about half-ebb-tide. 



The endeavour made by the author during his resi- 

 dence in England to identify this Zoantharian with any 

 previously known type has, while failing to elicit the 



mformation sought, given rise to interesting and debatable speculations concerning its actual 

 affinities. A Zoantharian that secretes a tubular " sclerobase " has hitherto been unknown in 

 the annals ol zoophytology, and is consequently looked at somewhat askance by authorities 



Dried Skeletal Tube of Acrozoanthus 

 Australia;, Nov. gen., n.sp., 73 nat. 

 size : delineated from two separate points 

 of view. 



