FOOD AND ENEMIES OF ANNELIDES. 265 



corallines, millepores and algae, and arrest them quickly ere 

 they can vanish in the sand. 



But the annelides also are liable to many persecutions. The 

 fishes are perpetually at war with them ; and when an impru- 

 dent annelide quits its hidden lurking-place, or is uncovered by 

 the motion of the waves, it may reckon itself fortunate, indeed, 

 if it escapes the greedy teeth of an eel or a flat-fish. It is even 

 affirmed of the latter, as it is of the whelks, that they know perfectly 

 well how to dig the annelides out of the sand. The sea-spiders, 

 lobsters, and other Crustacea are the more dangerous, as their 

 hard shells render them perfectly invulnerable by the bristling 

 weapons of the annelides. 



While the greater part of these worms lead a vagrant life, 

 others, like secluded hermits, dwell in self-constructed retreats 

 which they never leave. Their cells, which they begin to form 

 very soon after having left the egg, and which they afterwards 

 continue extending and widening according to the exigencies of 

 their growth, generally consist of a hard calcareous mass ; but 

 sometimes they are leathery or parchment-like tubes, secreted by 

 the skin of the animal, not however forming, as in the mollusks, 

 an integral part of the body, but remaining quite unconnected 

 with it. Thus these tubicole annelides spend their whole life 

 within doors, only now and then peeping out of their prison 

 with the front part of their head. 



As they lead so different a life from their roaming relations, 

 their internal structure is very different, for where is the being 

 whose organisation does not perfectly harmonise with his wants? 

 Thus, we find here no bristling feet or lateral respiratory ap- 

 pendages ; but instead of these organs, which in this case would 

 be completely useless, we find the head surmounted by a beauti- 

 ful crown of feathery tentaculae, which equally serve for breathing 

 and the seizing of a passing prey. Completely closed at the in 

 ferior extremity, the tube shows us at its upper end a round 

 opening, the only window through which our hermit can 

 peep into the world, seize his food, and refresh his blood by 

 exposing his floating branchiae to the vivifying influence of the 

 water. 



Do not, therefore, reproach him with vanity or curiosity, if 

 you see him so often protrude his magnificently decorated 

 head; but rejoice rather that this habit, to which necessity 



