146 



THE NATURALIST IN AUSTRALIA. 



for the erect foliaceous character of its coralla, which in many instances took a very 

 elegant and symmetrically convoluted scroll-like contour, and has on this account been 

 associated by the writer with the title of Montipora circinata. This species was not so 

 remarkable for its colour, being usually of a pale pinkish-red hue, with lighter 

 edges, but was at the same time conspicuous through the circumstance of its 

 growing in deep water in distinctly isolated patches of many square yards in extent. 

 The more matured coralla not unfrequently attain to a height of as much as three 

 feet, and, seen in masses in the crystal water beneath the boat, might be readily 

 mistaken for beds of broadly foliaceous plants. A photograph of an example of this 

 type, viewed vertically to illustrate its spirally convoluted growth pattern, is given 

 life size in the upper half of Plate XXIV. A lateral view of the same specimen is 

 also reproduced on a smaller scale in the accompanying figure. 



In connection with the subject of the Houtman's Abrolhos Madreporidae, it is 

 worthy of remark that nowhere perhaps do such facilities exist for making a systematic 

 record of the growth rate of tropical species as here. Many of the component 



reefs and lagoons are so sheltered and 

 so readily accessible that the necessary 

 measurements, observations, and experi- 

 mental cultivations could be carried on at 

 all seasons. In support of this suggestion, 

 it may be mentioned that the coralla of 

 various species of Madrepora have already 

 established themselves upon the basement 

 of the stone jetty constructed by Messrs. 

 Broadhurst and Co. on Rat Island, in the 

 Easter group, for the shipment of guano. 

 Certain of these taking the form of cauli- 

 flower-like clusters, and having a diameter 

 of some nine or ten inches, represented, 

 the writer was informed, a growth of less 

 than two years ; while smaller examples, 

 with a diameter of three or four inches 

 only, had been built up within the interval 

 of a twelvemonth. It is noteworthy to 

 observe that these Madrepora clusters were 



W. Knr',lti-K<nl, Photo. 



PF.LSART ISLAND SCROLL CORAL, 3fontipora cirrinatfl. 



TWO-FIFTHS NATURAL SIX.K. 



