see HOMOLOGIES. 
In no group of the Animal Kingdom is the 
fertility of invention more striking than in 
the Crinoids. They seem like the productions — 
of one who handles his work with an infinite 
ease and delight, taking pleasure in presenting 
the same thought under a thousand different as- 
pects. Some new cut of the plates, some slight 
change in their relative position, is constantly va- 
rying their outlines, from a close cup to an open 
crown, from the long pear-shaped oval of the 
calyx in some to its circular or square or pentag- 
onal form in others. An angle that is simple 
in one projects by a fold of the surface and be- 
comes a fluted column in another; a plate that 
was smooth but now has here a symmetrical figure 
upon it drawn in beaded lines; the stem which 
is perfectly unbroken in one, except by the trans- 
verse divisions common to them all, in the next 
puts out feathery plumes at every such transverse 
break. In some the plates of the stem are all 
rigid and firmly soldered together; in others they 
are articulated upon each other in such a manner 
as to give it the greatest flexibility, and allow 
the seeming flower to wave and bend upon its 
stalk. It would require an endless number of 
Ulustrations to give even a faint idea of the vari- 
ety of these fossil Crinoids There is no change 
that the fancy can suggest within the limits of 
the same structure that does not find expression 
