u 8 E X P L A N A T I O N OF THE TABLES.
F i g . I8. 19. 20. 21.
Rc^refcnt parts which are difperfed over the outfide of the iliell in the interfticcs
of the thorns or feet. They are articulated with it by mufcular ligaments,
and fupported on foHd cretaceous foot-ftalks. Beyond the foot-ftalks
thefe bodies are foft and moveable ; and at tlieir points fome cretaceous particles
are intermixed with the foft parts.
There are three varieties of thefe bodies. Two of the varieties agree nearly
in iliape, but differ in fize.
In F I G. 18.
A B , Reprefcnt the tliorns or feet. CDE reprefent the three varieties of thefe
moving bodies.
F I G. 19. 20. 21.
Show the fame bodies apart 5 and they are magnified to about two diameters
in all thefe figures.
