114 THE HALL OF SHELLS. 
formed almost entirely from their broken stems 
and flowers. 
“Once the glory of the sea, they have 
dwindled to a few species, inhabiting for the 
most part the deepest seas.” 
The following may be helpful in giving an 
understanding of the classes of Hehinodermata. 
First we have the Crinoidea, which are really 
stalked starfishes, the body mounted upon a 
stem which is jointed and hollow; second, the 
A steroidea, which are free and have five arms; 
third, Achinoidea, having a spherical body, 
with long spines; fourth, the Holothuroide, 
having elongated bodies, with skin soft or 
muscular. 
