142 THE NATURALIST IN AUSTRALIA. 
matic zoologists with whom small or fragmentary specimens alone have been hitherto 
available for classificatory purposes. In recognition of the multitudinous growth-forms 
exhibited by this particular coral, it is proposed here to provisionally distinguish it by 
the suggestive title of Madrepora proteijformis. 
Many of the areas of the Abrolhos reefs were characterised by an interblending 
of all of the various species of Madrepore enumerated in the foregoing paragraphs. 
The author's attention was, however, particularly impressed by the very definite 
border-like plan of their growth upon each side of the numerous river-like channels 
which circulate through the Pelsart Island Lagoon. In the regularity of their 
development and blended tints they vied, on colossal lines, with the artificially laid out 
flower-parterres of a well-appointed garden. 
The endeavour has been made by the author in Chromo-Plate IV., facing 
page 144, to commit to paper a faint and necessarily very inadequate idea of the 
unique and remarkably beautiful spectacle yielded by an area occupied chiefly by the 
violet-tinted Madrepora, as seen and roughly sketched while standing in the bows of a 
small row boat, and drifting down one of the intersecting channels. Through the 
glass-clear water in the immediate foreground every coral branch was distinctly visible, 
the clustered coralla in many instances constituting harbours of refuge to parrot and 
other fishes of the most brilliant hues, which would dart to and fro across the inter- 
vening spaces as the boat approached. 
The horizon line, looking oceanwards, as shown in this sketch, was, in its way, 
almost equally remarkable. The boundary in this direction is represented by the levelly 
raised surface of the rocky platform, which constitutes a massive breakwater between 
the placid waters of the lagoon and the tumultuous billows, which break unceasingly, 
and with a sustained roar mightier than that of Niagara, upon the precipitous edge 
of the outer barrier. An attempt has been made to portray the singular appear- 
ance of the rebounding columns of water thrown up against the horizon - line 
by the breaking waves, the altitude of which is optically greatly enhanced 
by mirage. This atmospheric phenomenon is here, as throughout tropical seas, of 
general occurrence. As an illustration of its prevalence, the very low points 
of the archipelago of islands that enter into the composition of the Houtman’s 
Abrolhos commonly appear to be elevated to an abnormal height above the horizon. 
A little further north, on the adjacent Western Australian coast, it is by no means 
unusual, as the effect of mirage, for the passenger steamers to discover the boats of 
the pearling fleets, or it may be of other denominations, some hours before they are 
