I 



BY THE REV. J. E. TENISON- WOODS, E.G.S., F.L.S., ETC. 197 



blocks of dead coral or at least searches for its food amongst 

 them. Though the spines are stout and the test is uncommonly 

 strong, it is very difficult to detach it from the crevice in which 

 it wedges itself. The only specimen seen by me in this way was 

 in a narrow groove or furrow on the side of a Solenastrcea. Its 

 beautiful brown spines with their bands of white and orange 

 made it a conspicuous object, the water was too dee^) for anything 

 but a long boat-hook, and then with every effort I could not 

 detachit. The species has avery wide range throughoutthe Pacific. 



Echinometra lucimtur, Leske. This is certainly the most common 

 urchin throughout the tropics, and I believe it is as common in 

 the Pacific as it is in Australia. I always found it under stones 

 or blocks of dead coral upon the reefs. I never saw it attach 

 itself to any object, but it moves rather quickly for an urchin 

 when its hiding place is discovered. Hundreds can be gathered 

 at every low tide upon the reefs. Sometimes as many as half a 

 dozen will be found imder a single block of stone. The colour 

 is very variable, and guite different from the appearance presented 

 by dried specimens in cabinets. The younger individuals are a 

 delicate fawn colour, and then there is every variation from pale 

 grey to black, or black and white. It is seldom that in a group 

 two urchins are of the same colour. I don't know of any species 

 which offers greater facilities for the stud}^ of the habits of sea 

 urchins. Its abundance on places where it can be easily observed 

 and its habits all favour remarks on its life history. In this and 

 the preceding species, it does not seem to me, that there are any 

 suckers around the actinosome, or at least that they do not attach 

 themselves to any object by means of them. In all those urchins 

 which attach themseles I notice a great flatness about the 

 actinosome and the ambulacral j)ores are spread out over a much 

 wider surface, I presimie it is by means of the tubes of these areas, 

 that the animal fixed itself firmly to the surfaces of the rock. In 

 Seterocentrohis mammiUatus and Ecliinometra lucunter, the region 

 round the actinosome is rounded. 



