65 



As regards the question ^ whether Hololhurians live on 

 living coral or obtain nutriment from swallowing the sand and 

 detrital material, the two most abundant species in the Gulf 

 of Manaar {H. atra and H. marmorata) live, not on the reef, but 

 on the muddy bottom between the reef and the shore, which 

 is frequently uncovered at low tide. From repeated exami- 

 nation of the contents of their alimentary canal, I have been 

 unable to find any evidence that they have been feeding on 

 living coral, the swallowed materials consisting, for the most 

 part, of sand, coral debris, small Mollusca, Alcyonian spicules, 

 and sea weeds. 



^ Vide Darwin, Coral Beefs, 3rd edition, 1889, p. 20. 



