PHOTOTYPE PLATES NOS. V. AND VI. 15 



NO. 2.-P0RITES ISLET, PORT DENISON. 



This reef-view, while belonging to the same district as the preceding one, represents an area 

 in the immediate neighbourhood of Adelaide Point on the mainland. The very conspicuous central 

 figure in this illustration is a grand mass of Porites, apparently identical with the variety that forms 

 the basis of the Thursday Island diagrammatic chart. Like that example, its exposed, horizontal, 

 surface is for the most part dead and eroded, vitality being visible along its lateral borders only. 

 The manner in which the most recent growths have developed, forming projecting lateral crests, is 

 worthy of note. As in the Thursday Island example, the eroded upper surface has been adopted 

 as a fulcrum of attachment by various coral types that flourish on a higher vertical plane, or, 

 in other words, are better capable of surviving atmospheric exposure than the Porites. Sub- 

 spheroidal Goniastrseae and a corymbose Madrepora, M. convc.xa, represent the most conspicuous 

 species in this instance. A more clearly-defined example of the Madrepora is included in the 

 nearer foreground, while numerous coralla of the same species of Goniastrsea are thickly crowded 

 in the background towards the left. Such is the ovate s^'mmetry and peculiar incidence of the 

 light upon these Goniastreeas that, it transported to an ordinarj- landscape, they would pass for 

 a flock of sheep. 



A noteworthy feature in this Adelaide Point reef-area is the abundant development thereon 

 of a luxuriant crop of seaweeds of the olivaceous or Melanospermous order. The weeds are 

 of slighter structure than the ordinary European Fucaceae ; but one dominant variety closely 

 resembles the so-called Peacock-weed, Pavonia padina, of the British seas. An extensive 

 crop of these algas, mixed with coral growths, is conspicuous in the foreground of this Porites 

 Islet reef. 



PLATE VI. 



NO. l.-PORITES ISLETS, FILM ISLSNDS, 



This illustration represents a small portion of the outermost, tidally exposed, boundary of the 

 reef whose inshore area has already been the subject of delineation and description. Two out of 

 the three little coral islets included in this reef-view are, as in the preceding case, represented hy 

 a solid basement of Porites astro'oidcs, or a very nearly' allied form, upon whose eroded upper surface 

 other coral species have become established. On the larger, or central, islet of the group, a 

 considerable number of varieties may be recognised, including, most conspicuously, a finely- 

 developed Brain-stone coral belonging to the genus Maeandrina. The Porites basement in these 

 two larger islets were coloured brilliant mauve, the same tint characterising the majority of the 

 massive coralla of this species throughout the Palm Islands district. A point of interest that 

 attaches itself to this little islet group is the circumstance that, in their varying conditions of 

 development, the respective islets may be said to epitomise the several most characteristic 



