CORALS AND CORAL-ANIMALS. 147 



the primary subdivisions of a twenty-four hour timepiece) which correspond with the twenty- 

 four inter-tentacular radii. These shorter Hnes are, in the photographic illustration, for the 

 most part obscured by the basal ramifications of the tentacles. A consecutive series of five of 

 them, however, are distinctly visible towards the upper right-hand corner. The basal halves 

 oi the main shafts of the tentacles in the example photographed were alternately of a pale 

 lilac and pale sea-green hue, their ultimate ramifications, and also the ground tints of the coral 

 disk, being represented by shades of grey and bulT. Although occurring under similar 

 conditions, this anemone does not, generally, root itself as firmly and deeply to underlying 

 rocks as does the Actinodendron. It, moreover, does not possess the distinct urticating 

 properties that obtain in its ally, and it may therefore be handled with impunity, or, as 

 was the case with the specimen figured, be detached and transported without mutilation 

 for leisurely observation. As explained in the mention of this anemone given in the de- 

 scriptive account of Plate XXII., p. 35, it is referable to the genus Megalactis of Ehrenberg, 

 while, as a new species of that genus, it is associated in this volume with the distinctive title 

 of Megalactis Grijfithsi. 



The sea-anemones of the Great Barrier Reef district that are most remarkable for combined 

 beauty of colour and structure are undoubtedly those referable to the genus Heterodactyla. 

 In this group, the tentacles are for the most part plumose in character and developed in tufts, 

 or in the form of a closely-set pile throughout the greater area of the surface of the expanded 

 disk. Interspersed among the tentacles, and representing structural modifications of these organs, 

 are clusters of spheroidal-shaped bodies that are remarkable for their jewel-like brilliancy. 

 In the larger species of the genus, apparently identical with the Red Sea Heterodactyla 

 Hemprichii, obtained from the Albany Pass, Torres Strait, and also from the Barrier Reef off Cape 

 Flattery, the expanded disk is somewhat irregularly lobate and four or five inches in diameter. 

 The short supporting stalk, or column, is pale pink, variegated with regularly developed longi- 

 tudinal lines of carmine spots. The centre of the expanded disk, in the vicinity of the mouth, is 

 a pale lemon-yellow, its peripheral border a light olive-brown, and the intermediate area a varie- 

 gated mixture of both these tints. The tentacles in this species are more or less distinctly 

 pinnate, developed singly or in interrupted rows near the centre of the disk, becoming more 

 thickly massed as they approach the peripheral border. The tentacles appear superficially 

 to be of a yellowish-brown hue, but, examined with a lens, they are found to be transparent 

 lemon-yellow with a central olive-brown core, which is continued throughout the main shaft into 

 their pinnules. The jewel-like clusters are developed only along the peripheral border of the 

 disk ; but, as seen isolated, they consist of tentacles so modified that in many cases the 

 distal pinnules retain their normal character. In other instances, the same structural modifica- 

 tion has so far progressed tliat the entire series of pinnules are replaced by the spheroidal 

 organs. 



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