There is no change that the fancy can suggest
within the limits of the same structure that does not find expression
among them. Since I have become intimate with their wonderful
complications, I have sometimes amused myself with anticipating some
new variation of the theme, by the introduction of some undescribed
structural complication, and then seeking for it among the specimens
at my command, and I have never failed to find it in one or other of
these ever-changing forms.
The modern Crinoid without stem, or the Comatula, though agreeing with
the ancient in all the essential elements of structure, differs from it
in some specific features. It drops its stem when full-grown, though
the ab-oral region still remains the predominant part of the body and
retains its cup-like or calyx-like form. The Comatulae are not
abundant, and though represented by a number of Species, yet the type
as it exists at present is meagre in comparison to its richness in
former times. Indeed, this group of Echinoderms, which in the earliest
periods was the exponent of all its kind, has dwindled gradually, in
proportion as other representatives of the Class have come in, and
there exists only one species now, the Pentacrinus of the West Indies,
which retains its stem in its adult condition.
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