266 THE WORLD OF THE SEA. 
lived in harmony, and then the greater of the two attempted to 
eat his companion. He managed to get part of his body into 
his great cesophagus trunk ; his victim made desperate efforts to 
disengage himself, and after a time succeeded; but, unhappily 
for him, during the combat he had had some of his scales torn 
off, and his rings damaged. The next day there only remained 
half, for during the night the conquest had been completed, the 
rest had been devoured; and the conqueror was darting hither 
and thither his hungry proboscis erect, ready to seize the remain- 
der of the little creature, which had shrunk into a corner of the 
aquarium. 
The dorsibranchiata are wanderers; the tubicola are fixed. 
These latter are noted for the elegance of their respiratory organs, 
which are ranged sometimes in plumes, sometimes in crowns, or 
in fans. The entrance to their habitation is ordinarily small; it 
is, however, the only opening through which these recluses can 
have any communication with the world around them. Foremost 
amongst these annelids we must mention the Zermeles. They live 
in the waters of the Mediterranean, lodged in a tube of sand 
some three inches long. Out of the end of the pipe from time 
to time there issues a bifurcated head; from the summit of each 
branch a number of strong, sharp tongues, of a golden yellow, 
rise; these close over the entrance of the holes whenever the 
creature is disturbed and retreats into its mansion of sand. The 
least motion which makes a ripple upon the surface of the water 
is sufficient to cause the timid animal to shut itself up in its 
fortification. From the sides of this cephalous defence, fifty or 
sixty delicate, violet filaments issue, which are in continual motion. 
Like so many little serpents, they alternately lengthen and shorten 
themselves, seizing their prey as it passes, and drawing it into the 
mouth. 
To their activity and energy the annelid owes its dwelling- 
house: they gather the grains of sand, and build up its incasing 
tube; the solid grains are held together by a kind of mucus, 
which, in fact, plays the part of an hydraulic mortar. Upon the 
sides of the body.may be noticed mammillary risings, out of 
the summit of which issue sharp, cutting lances; these are, in 
fact, the feet of the creature. 
