TUBICOLA. 365 



formed by an exudation from the skin, of a glutinous 

 nature, which either hardens into a simple horny 

 covering, or else, as is more frequent, becomes a 

 sort of shell by the adhesion of grains of sand, bits 

 of shells, and other matters to its surface. The 

 Terebella Conchilega,* for example, unfolding the 

 coils of its body, extends its large tentacles in every 

 direction, in search of fragments of shells. These 

 it drags to its head, fastens them in a sort of ring 

 or collar, by means of a gummy matter, and, by 

 lengthening this, forms a tube prettily studded 

 with little shells. The similarity of this process 

 to that of the Caddis-worm, (Phryganeaj) is remark- 

 able and interesting. 



Many of the Order have, to a greater or less 

 extent, the power of boring, not only into sand, but 

 into solid substances, such as wood, sponges, corals, 

 and even rocks ; they feed on very small animals, 

 which they catch with their tentacles. 



* Diminutive of Terebra, a little borer ; xoyxn, konche, a shell, and 

 \iyu, lego, to collect. 



