286 LITTLE FOLKS 
little Worm, with very beautiful tentacles, or gill-fans. The Sabella 
— who has all the polyps about his door — has a crowd of feathery 
tentacles, and the Serpula, another tube building cousin, has elegant 
gill-fans. When the creature comes to the door, he pushes out 
these beautiful appendages and spreads them out in their full glory 
in the water. The object is the same in each one, to breathe and 
to get something to eat. 
The feeding is a curious process, consisting in keeping up a 
current of sea water into the creature's mouth. The current is 
kept up by the motion of a part of these spreading organs, and as 
the water rushes in, he seizes what is good to eat, and the rest goes 
through and serves the useful purpose of washing out his house. 
So he gets his dinner and cleans house by the same operation. 
This performance you can see, if you have any of the family 
in an aquarium — provided you are very still — but move about, or 
even raise your hand, and down goes the beautiful creature into his 
house, shutting the door behind him, if he is one of the kind who 
has a door. I must tell you how he manages to get out of sight so 
quickly ; the whole thing has been found out by these untiring fel- 
lows with microscopes. 
To get up to the door of his house the little creature has a set 
of pushing poles. They are stuck out through some warty looking 
projection on his body, one row on each side. From each projec- 
tion comes a bunch of stiff spear shaped bristles, twenty or thirty 
in a bunch, and they push against the membraneous lining of his 
tube, thus carrying him easily to the door. 
But going back is quite another matter ; he can take his time 
in coming out, and he does usually, but he wants to go back like a 
flash, if he thinks there's danger abroad. For this purpose he has 
the most astonishing arrangement, no less than ten or twelve thou- 
sand hooks on his little body, which all act together and instantly. 
No wonder he can shoot into his house so quickly that you can not 
see him. What wondrous provision for the safety and comfort of 
one little worm less than an inch long ! 
I told you the little creature could shut his door, and so he 
can — if he's one of the Serpula family — but I haven't told you 
about the door, and that is as interesting as anything about him. 
What we call the door, is in fact a stopper, like a cork, and when 
the gill-fans are out, it hangs at the side of the tube, at the end of a 
slender thread-like arm. But when they fold up and shoot in, the 
