264 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
socket joint, and provided with muscles at its base. 
On the external surface, besides the spines, we 
Fig. 38.—A Lily-star. (From Cassell’s “ Nat. Hist.’’) 
meet with pedicellariz (Fig. 33 magnified), and also 
with the madreporic tubercle (Fig. 39, m). The 
pedicellarize in their main features resemble those 
