PHOTOTYPE PLATES NOS. III. AND IV. n 



Alcj-onaria. These include, immediately to the rear of the charted area, a considerable surface 

 that is entirely encrusted with a corrugated-leather-like species, apparently identical with the 

 AlcyoniiuH mumlc of Dana, that is yet more extensively developed, and herein fully described, in 

 association with the lower of the two reef-views included in Plate XX. 



It remains to be mentioned that the high ground on the farther side of the water in Plate II. 

 represents a portion of Prince of Wales's Island, with its scattered pearl-shelling stations. These 

 landmarks should prove of service in making a re-survey of this reef-area. A like condition 

 of the tide and the same bearings being accurately obtained, a photograph taken a decade or 

 two hence should reveal important data concerning coral-growth in this region. 



PLATE III. 



ISOLATED CORAL-GROWTHS, CHARTED REEF, THURSDAY ISLAND. 



This illustration represents a nearer view of the coral-growths that occupy the foreground of 

 the preceding plate, but from an opposite standpoint, looking shorewards instead of seawards. 

 The identical coralla of the Goniastraea and Symphyllia are here shown to much greater advan- 

 tage, the minute individual cells of the former, and the elegantly convoluted ridges and valleys 

 of the latter, being remarkably distinct. The life-colour of this individual Brain-coral was a rich 

 golden-brown ; it frequently happened, however, that while the septal ridges e.xhibited this golden 

 tint the intervening valleys, or polyp-centres, were a rich velvety green. A fragment of such a 

 more brightly-tinted variety is illustrated in Plate V. of the coloured series. Several coralla of 

 the narrower-celled, ordinary Brain-coral occupy a somewhat lower level in this picture. The 

 life-colours of these specimens were, when examined, lilac and brown, the former tint distinguish- 

 ing the valley-like depressions, and the latter the intervening ridges. A coloured representation 

 of this type is given in the plate last quoted. 



A noticeable feature in Plate III. is the background, consisting of a mass of lifeless 

 sedimentary coral-rock encrusted with growing Alcyonaria of diverse varieties. Towards the 

 right may be observed the fleshy, lobulated polyparies of Sarcophyton (Alcyojiiitm) glaitciim; the 

 middle ground is occupied by Alcyoiiinm Jlc.xibilc, and the left-hand area by the proliferous colony- 

 stocks of a species of Ammothea. The extent of surface that may be covered by these soft- 

 fleshed representatives of the coral class is even more abundantly demonstrated in several sub- 

 sequent illustrations, including, notably. Plates XX. and XXI. 



PLATE IV. 



NO. l.-INSHORE REEF, PALM ISLANDS. 



This view is highly typical of the class of coral-reef that predominates on the intra-tidal 

 areas of the Palm Islands group. It represents a portion of the foreshore that is left high and 



C 2 



