THE SHELL-BINDER. 529 



To give the Sabella a variety of building materials, and to note which it accepts, is always 

 an interesting amusement ; for the worm is very fastidious, not to say capricious, in its 

 choice, and always likes to have a stock of materials from whicli it may make its selection. 



While wandering along sandy coasts, we frequently come across some moderately large 

 tubes projecting from the sand, and rather conspicuous in the little puddles left by the 

 receding tide. Round their mouth is usually a set of forked filaments which, like the tube 

 itself, are composed of fragments of sand agglutinated together. The substance of this tube 

 is very soft, but very tough, and will endure a tolerably hard pull without breaking. If 

 the inhabitant of these tubes be sought, it will not be found without much labor, for the 

 TEREBELLA retreats to the farther extremity at the least indication of danger ; and as the 

 tube is a foot or more in length, and is always conducted under stones or among rocks, it is 

 not easily dislodged. 



As in the case of the Sabella, this annelid performs its architectural labors by means of its 

 tentacles, which are most wonderfully constructed, so as to be capable of extension or retraction, 

 and at the same time can seize or throw away a particle of sand at any part of the tentacle. 

 The method of working is very well given by Mr. T. Rymer Jones: "If a specimen be 

 dislodged from its tube, it swims by violent contortions in the water, after the manner of 

 various marine annelids ; the tentaculae and the branchiae are compressed and contracted about 

 the head, like a brush ; and as the animal is very soon exhausted by such unnatural exertions, 

 it soon sinks to the bottom. Should a quantity of sand be now scattered from above, the 

 tentaculse, speedily relaxing, extend themselves in all directions to gather it up, sweeping the 

 vessel quite clean, so that in a very short time not a particle is left behind that is within their 

 reach, the whole having been collected to be employed in the construction of a new artificial 

 dwelling, adapted to shelter the naked body of the architect. 



"We will suppose a tube to have been partially constructed into the side of the aquarium, 

 wherein a specimen is about to take up its permanent abode. During the earlier part of the 

 day, the animal is found lurking in its interior, with only the extremities of the tentaculae 

 protruding beyond the orifice, and so it will remain till towards noon. 



"But scarcely has the sun passed the meridian, than the creature begins to become restless ; 

 and towards four or five it will be seen to have risen upwards, the tentaculse extending with 

 the approach of evening, until after sunset, when they are in full activity. They are now 

 spread out from the orifice of the tube like so many slender cords each seizes on one or more 

 grains of sand, and drags its burden to the summit of the tube, there to be employed according 

 to the service required. Should any of the tentacula? slip their hold, the same organs are 

 again employed to search eagerly for the lost particle of sand, which is again seized and 

 dragged towards its destination. 



"Such operations are protracted during several hours, though so gradually as to be 

 apparently of little effect. Nevertheless, on resuming inspection next morning, a surprising 

 elongation of the tube will be discovered ; or, perhaps, instead of a simple accession to its 

 walls, the orifice will be surrounded by forking threads of sandy particles agglutinated 

 together." 



There are many species of Terebella. They have, to a considerable extent, the power of 

 reproducing lost portions of the body ; and it has been found that even the whole mass of 

 plumy tentacles can be removed without much injury to the Terebella, which retreats to its, 

 tube, and after a while reproduces the whole of the missing organs. 



The SHELL-BINDER is very plentiful on some coasts, especially those where the shells of 

 various mollusks are found in profusion. The tube of this species is built almost entirely 

 of little fragments of shell, and is of very great length so long, indeed, and going so deeply 

 into the sand and among the stones, that to procure a perfect specimen is almost an impossi- 

 bility, except by some rare good fortune. As this creature makes its dwelling about midway 

 between high and low water mark, it may sometimes be procured by setting to work as soon 

 as the tide has retreated, and, with crowbar, pick, and shovel, making the best use of the few 

 hours that can be given to the task. I have never yet succeeded in extracting an entire tube, 

 though I have often tried to do so. 



