16 THE OCEAN. 
to the tip, representing the vane. Along the upper 
edge of each of these pinne are placed the cells, 
inhabited by minute, white, eight-rayed Polypes. 
The stem contains a long, needle-shaped bone, very 
slender at each extremity, which is bent backwards 
so as to forma hook. Some authors have affirmed 
that the Sea-pen swims freely in the sea by the 
waving motion of its pinne; but modern observa- 
tions tend to throw discredit on this statement, 
which in itself seems improbable: the fishermen 
affirm that it abides with its stem inserted in the 
mud at the bottom; and those which have been 
kept for observation have remained at the bottom 
of the vessel, without any apparent power. of even 
turning over on the other side. This species, as 
its scientific name imports, is one of the many ani- 
mals that inhabit the sea, which are endowed with 
the faculty of producing light: in this instance, it 
appears from experiments that the power is exerted 
as a means of defence, as only when injured or irri- 
tated does the animal give out its light, which is of 
‘a faint-bluish cast. Its sudden illumination at the 
bottom of the sea may have the effect of terrifying 
some of its enemies, and of thus protecting it from 
the dangers to which its otherwise helpless frame 
would be exposed. 
