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 beauiti- 
ful crown of feathery tentaculz, 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 branchiz 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 
