PHOTOTYPE PLATE NO. XXV 39 



PLATE XXV. 



CORILS WITH EXPANDED POLYPS. 



The figures included in this plate typify the living aspect ot three essentially distinct 

 coral genera. The first portra^-s a small colony-stock of Goniopora, apparently identical with 

 G. lobata, the living polyps of which, in this specimen, were scarcely distinguishable in form and 

 colour from those of Rhodarcea fniticosa, illustrated by Plate VI., Fig. 4, of the chromo-lithograph 

 series, the centres of the disks, or peristomes, and the tops of the tentacles bemg white, and 

 the remaining surfaces a clear liver-brown. In common with other representative forms of the 

 same genus, the polyps are capable of protrusion to a very considerable distance beyond the 

 orifices of their corallites. In the photographic illustration given, these organs were only 

 semi-extended. Other figures of the same coral, included in the coloured plate, will suffice to 

 indicate the extensive range of colour variation that a single specific form may exhibit. 



The second figure represents a small colony-stock of Enphyllia rugosa attached to a dead 

 branchlet of a Madrepora. The polyps in this instance, also, are only partially extended ; but 

 they exhibit at many points their characteristic capitate contour. The fine granulated texture 

 of their cylindrical shafts is distinct in silver prints from the original negative, and is discern- 

 ible, with the aid of a hand-lens, in the mezzo reproduction. Illustrations of the colour varia- 

 tion to which this species is subject are abundantly given in Plate IV. of the chromo- 

 type series. The example photographically reproduced corresponded, among these, with the 

 variety in which the shafts of all the tentacles were a delicate lilac, and their inflated 

 extremities a pale apple-green. Both this and the Goniopora previously figured were obtained 

 at Adolphus Island, Torres Strait, and photographed in extemporised aquaria on board H.M.S. 

 Rambler. 



The third or lowest figure in Plate XXV. depicts a mature corallum of Pectinia Jardiiiei, of 

 which a young, fully-expanded colony-stock, coloured from life, is represented in Plate IV., Fig. 7, 

 of the chromo series. It undoubtedly represents one of the most beautifully-tinted members of 

 its class, constituting, when fully extended, a very attractive object. This coral has been 

 collected by the author on the Warrior Island reef, and also in the vicinity of the Albany 

 Pass, Torres Strait. Like the Euphylliae, to which it is allied, it is apparently limited in 

 its distribution to the equatorial zone. As shown in the coloured illustration, the corallum 

 terminates inferiorly in a slender footstalk or pedicle, and is, in its earliest condition of 

 development, attached to some supporting fulcrum. In all examples, however, collected by 

 the author, including specimens less than half the size of the coloured one, the coralla were 

 lying freely on the reef, and had evidently become detached at a very early period of their 

 development. As thus collected in their natural condition, mostly just covered by the retreated 



