SEA-FAN MAKERS. 



191 



Professor Perceval Wright found masses, as much as 

 2 ft. in diameter, in the Seychelles, although, more 

 commonly, in irregular lumps of about 12 in. in 

 circumference, and from 2 in. to 4 in. in height. We 

 are indebted to him for the description of the animals 

 which inhabit, and construct, these tubes, as he had 

 the good fortune of seeing them in the living state. 

 " The polyp," he says, " consists of eight pinnate 

 tentacles, each tentacle with from fifteen to seventeen 

 pennae on each side ; these 

 tentacles are thickly studded 

 with spicules of an oval shape, 

 flat, somewhat longer than 

 broad ; and are met with all 

 over the tentacle, down the 

 centre of which there is one 

 compact row, forming, as it 

 were, a mid-rib ; they are 

 often slightly compressed in 

 the centre, so as to form a 

 figure of eight. In the centre of the tentacles is 

 the mouth, with a slightly raised circular lip. When 

 the polyp is alarmed the tentacles are first closed 

 together, and then the polyp sinks down quite into 

 the tube ; as it becomes more completely retracted 

 it draws in after it the uppermost portion of the tube 

 itself, inverting this, and folding it in until the open 

 mouth of the tube is thereby_completely filled. It 



FIG. 34. ORGAN CORAL 

 ( Tubipora nmsica). 



