266 THE OCEAN WORLD, 
of this stem are usually very numerous, cylindrical, and present a series 
of rays striated upon their articulated faces. In Pentacrinus they are 
Fig. 107, —Pentacrinus europzus (Thompson). 
prismatic and pentagonal; that is, they present five projecting angles, 
and on their articulated face a star with five branches, or, better still, 
