THE TEREBELLA. 127 



presently the entire plume is twisted round in the mouth of the 

 tube, and it will be a wonder if, in a moment after, some slight 

 movement of the observer himself do not send the little worms, 

 quick as lightning, out of sight. 



Not unfrequently, groups of Serpula? may be found, in which 

 two or three individuals of the larger species have secreted their 

 tubes in a sort of coil, which stands up nearly erect from some 

 stone or shell, while several of the smaller species cling on to 

 them in various positions, like climbing plants attached to the 

 trunk of a tree. We once had a group of this description, in 

 which the central support was formed by three large specimens of 

 8. contortuplicata lovingly embracing each other, and putting 

 their heads close together at the top, while attached to them, at 

 different points, there were no less than ten individuals of smaller 

 species of Serpulae, and two tube-making worms of another order 5 

 and we can assure our readers that when the entire group were 

 in good humour, and put out to the full their variously-tinted 

 plumes, they formed a spectacle of rare interest and beauty. It 

 was really nothing less than a bouquet of worms. 



In another race of tube-making Annelids, closely allied to the 

 Serpulce, the domicile is formed, not by the secretion of lime 

 from the body of the worm, but by a sort of masonry, the worm 

 regularly building up its tube with particles of sand and frag- 

 ments of shell. By far the best known of these worms is the 

 Terebella (Terebella conchilega), which is extremely abundant on 

 sandy shores between the tide marks, and may often be seen in 

 shallow depressions of the surface, waving about its numerous 

 thread-like tentacles, very busily engaged, apparently, in doing 

 nothing. But it is not at all times that the Terebella is thus 

 idle ; and when the business of house-building is on hand, it has 

 to be its own hodman and bricklayer both. Its tentacles, how- 

 ever, are fully equal to the task, for as they are capable of great 

 extension and contraction, and are also provided with an ad- 

 hesive glutinous secretion, the animal is enabled to sweep the 

 sand for building materials for several inches around its burrow, 

 and to bring them home to the mouth of the tube. Here the 

 selected materials are regularly arranged, and attached to the 

 tube, by means of a kind of cement secreted by the worm, and 

 which forms at once the lining of the tube and the matrix in 

 which the fragments of which it is built are embedded. 



