FIVE-FINGERED JACK ON THE OYSTER. 
UITE as infinite in number, variety and form is the life 
\Y, of the seaas that of the land. But of all marine ani- 
mals, however, there is none more curious than the echino- 
derm, a name derived by science from two Greek words, 
indicating an animal bristling with spines like the hedge- 
hog. These creatures are sometimes free, but quite as often 
attached by a stem, flexible or otherwise, and radiate after 
the fashion of a circle or star, or are of the form of a star, 
with more or less elongated arms. They are covered with 
shell-like plates, which they secrete for themselves, and are 
still further protected by spines or scales. 
Perhaps the most common of the echinoderms is the Star- 
fish, or Five-fingered Jack, as it is called by sailors. Who- 
ever has spent any time on the seashore has doubtless made 
the acquaintance of this animal, for it is readily distinguish- 
able by its shape, its upper surface being rough and tuber- 
culous, and armed with spine-like projections, while the 
under portion is soft, containing the essential organs of life 
and locomotion. 
When first seen stranded on the shore the Star-fish, by 
the uninitiated, is thought to be a creature incapable of move- 
ment of any kind. But this is far from being the case, for 
in its native element it moves along the bottom of the sea 
with the greatest ease, being provided with an apparatus 
specially adapted for the purpose. Ordinarily its arms are 
kept upon the same level, but in passing over obstacles that 
lay in its path, the animal has the power of raising any one 
of its several arms. Elevations are ascended with the same 
