IN FEATHERS AND FUR. 285 
The tube on the edge of which they stand, is ^he home of a 
curious little fellow, which I will tell you about in a minute. When 
he sticks his head out, these wild creatures on the edge are quiet 
and rest against him, but the moment he goes into his house they 
commence their strange performances. 
The interesting little fellow, who lives in the tube, belongs to 
the family of Tube-building Worms, and his name is Sabella. His 
whole tube — or house — is not more than four inches long (and he 
is not an inch himself) and of course, it is not more than an eighth 
of an inch across, though it looks so large in the picture. 
Little as he is, he has some curious ways. To begin with, he 
always builds his own house, and he w T ould be as uncomfortable 
without one as you would. All his family build houses, though no 
two branches of it use the same material — some using sand, others 
mud, and still others preferring a hard shelly substance. They 
have often been made to build when in aquariums, and so the 
whole process is made known, and the description of one will do 
for the whole. 
When the little fellow wants to add to his house, he first pro- 
ceeds to collect materials by means of his numerous tentacles or 
arms. He then takes the substance, whether grains of sand or 
atoms of mud, one by one up in those arms, lays it on the edge 
and cements it there, where it soon hardens. Not having hands, 
perhaps you wonder how he manages to lift a grain of sand. 
Nothing is easier — or more wonderful. He can fold together the 
tiny atom of a tentacle, not fold up the end, but fold together from 
side to side, so he can take up a grain of sand anywhere on the whole 
length of each little arm. All his many arms work together, and 
it is surprising how rapidly he adds to the length of his house. 
That is not the only curious thing about the tiny mansion. 
When he began to build, he was a baby and only needed a small 
house, so it is very small at the end where it is fastened to a stone 
or shell. But as he grew and wanted to get out of the nursery, he 
built on a larger addition, and thus his tube gradually increases in 
size till it is right for the full grown builder. 
When this little fellow builds in an aquarium, it is interesting 
to give him different kinds of materials and see what a droll sort 
of a house he will make. 
Now you know about the house, I must tell you about the 
little fellow himself. He is nothing more nor less than a short 
