228 THE WORLD OF THE SEA. 
side. In one of the members of this species, these organs are so 
branched that they are characteristic of the animal, and to them 
it owes its name—Dendronotus arborescens. The respirators rise 
in six or seven pairs ; these branch off, and the branches are again 
subdivided into a great number of twigs. When the mollusk is 
at rest, the branches hang down on each other like the limp boughs 
DENDRONOTUS ARBORESCENS, 
of a dead shrub, and their great tentacles curl round like the horns 
of a ram. When in motion, the feelers are straightened and 
stretched out, as if to pioneer the animal on its way; the respi- 
ratory tubes are all stiffened, as if vigorously to supply air for 
the exertion of motion. 
The eolides are an irritable and quarrelsome people. They 
seize their prey with fury, and fight with each other violently ; 
often they retire from a combat in a sadly dilapidated condition, 
