THE TACIFIC OCEAK 255 



that tliey M^cre often mistaken for pieces of the rock ; 

 these were generally of a dark colour, and from foiir 

 to five inches long, and two or three round. AVhen 

 the rock was broken from a spot near the level of 

 high-water, it was found to he a hard, solid stone ; 

 but if any part of it were detached at a level to 

 which the tide reached every day, it was discovered 

 to be full of worms all of different lengths and 

 colours, some being as fine as a thread, and several 

 feet long, generally of a very bright yellow, and 

 sometimes of a blue colour ; while others resembled 

 snails, and some were not unlike lobsters or prawns 

 in shape, but soft, and not above two inches long."* 

 The animals thus described by the Captain, were 

 doubtless intruders that had sought shelter or food 

 in the interstices of the coral. I have myself observed 

 the number and variety of creatures, — Star-fishes, 

 Sea-cucumbers, Annelides, Crustacea, and minute 

 Fishes, that crowd about the broken coral of a tro- 

 pical reef The true architects of these wonderful 

 structures are polypes of minute size, which, though 

 of many varying species, and even genera, agree in 

 the simplicity of their form and structure. They 

 consist of a little oblong bag of jelly, closed at one 

 end, but having the other extremity open, and sur- 

 rounded by tentacles, usually six or eight in number, 

 set like the rays of a star. Multitudes of these tiny 

 creatures are associated in the secretion of a common 

 stony skeleton, the coral or madrepore ; in the minute 

 orifices of which they reside, protruding their mouths 

 and tentacles when under water, but withdrawing 



• Voyage to Loo-Choo, p. 75. 'Constable's edit.) 

 s2 



