34 THE GREAT BARRIER REEF. 



are remarkable for their stinging or urticating properties, the form represented by the upper 

 figure being most notable in this respect. The urticating property possessed by this type, 

 as personally tested, is nearly as powerful as that of an ordinary stinging-nettle, and the rash 

 produced on the skin through contact with the animal's stinging-cells or " cnidas " endures 

 for several days. The habits of this sea-anemone are very distinct from those of the succeed- 

 ing type, as it occurs most abundantly in the pools of water left on the sandy flats at half or 

 even one quarter ebb. The crown of tentacles, which only is visible in the accompanying plate, 

 surmounts an elongate, highly-contractile stalk, or column, penetrating the sand for eighteen 

 inches or more, and affixed to some rock or dead and buried coral boulder. The attempt to 

 dislodge the animal from the supporting fulcrum is almost invariably vain ; and, in order to 

 secure specimens without mutilating their elaborately branched tentacular crown, the plan 

 was resorted to of thrusting a sharp knife as far as possible down the side of the column and 

 there cutting it abruptly through. The photograph of the form here reproduced was taken 

 of the zoophyte while basking in situ in a sand-pool at Somerset, in the Albany Pass, the 

 narrower, but since the Quclta wreck most commonly adopted, entrance to Torres Strait for 

 vessels passing north from Queensland ports. 



Some difficulty has been experienced in identifying this species with any previously described 

 form ; the only one in which its essential features are to a certain extent symbolised being in the 

 very crude illustration and description of Actinodcndroii alcyoitoidciiin of Quoy and Gaimard, 

 contained in the "Voyage a I'Astralabe," 1833, with which type, in preference to multi- 

 plying specific titles, it has been thought advisable to allocate it. In this decision the author 

 is supported by Prof. A. C. Haddon, to whom this illustration was submitted, and by whom 

 the same species has been obtained from an adjacent locality. 



The life colours of this Actinodendron, compared with those of many other members of its 

 class, are lacking in brilliancy, being chiefly represented by varying shades of light brown and 

 white, which are probably conducive to its advantage by assimilating it to the tint of its sandy 

 bed. When fully extended, the compound tentacles are elevated to a height of eight or ten inches, 

 and bear a remarkable resemblance to certain of the delicately branching, light-brown seaweeds 

 that abound in its vicinity. 



The lower of the two figures in Plate XXII. represents a species which at first sight possesses 

 much in common with the foregoing form. The tentacles are, however, relatively more elongate 

 and more regularly pinnate, while the termination of each minute, ultimate, subdivision is per- 

 fectly simple, in place of being distinctly bifid. In respect to their plan of ramification, the 

 tentacles of this anemone accord with that structural type which, in a moss or fern frond, would 

 be termed by botanists " tri-pinnate," each primary pinnule being further subdivided into 

 secondary and tertiary pinnulas. In the preceding figure of Adiiiodeiuh-oii alcyonoidciim it is con- 

 spicuously manifest that the primary and secondary subdivisions of the tentacles, in place of 



