13^ 



CORALS 



There is one more interesting feature about the Plex- 

 auridae which is very difficult to account for, and that is that 

 in dried specimens the coenench^-m is nearly always white. 

 The colonies rarely present any of those brilliant colours 

 which are seen in the Gorgoniidae and Gorgonellidae. 



The old genus Plexaura has in recent years been split up 

 into a number of genera on the ground of differences in the 

 structure of spicules and in other characters which need not 

 concern us now, but the principal interest of this group of 

 genera is that the hard black axes are very largely used even 

 at the present day by the mariners of the Indian and Pacific 



Fig. 6o. — Plexaura. A part of a specimen from Torres Straits. Note the 

 thickness of the bark as seen on some of the terminal branches where the horny 

 a.xis projects. About i nat. size. 



Oceans to make into bracelets and other amulets as a pro- 

 tection against rheumatism and the dangers of the sea (see 

 p. 247). There can be little doubt that the Accarhaar itain 

 of the Malavs mentioned by Rumphius was a Plexaurid. 



It is difficult to determine with any degree of certainty 

 what the stony rushes (junci) were that the soldiers of 

 Alexander observed in the Indian seas. They may have 

 been Gorgonians of various kinds or possibly Antipatharia, 

 but nothing fits the description better than some of the 

 species of the Plexauridae. 



The last two families of these flexible corals do not 



