332 THE MEDALS OF CREATION. Cuap. IX. 
tacula, and their subdivisions, must be sought for, and if 
discovered, should be removed with the stone to which they 
are attached, and the block be afterwards reduced in size by 
a mason’s saw, and not by the blows of a hammer, which 
might displace the ossicula. 
If imbedded in Lias shale, or other fragile material, a 
thick slab should be removed, for greater safety in convey- 
ance; this, when reduced to a convenient size and thinness, 
may be imbedded in a tray with plaster of Paris, or glued 
to a piece of thin, well-seasoned mahogany, or deal. The 
specimens of the Pear Hncrinite of Bradford, and of the 
Pentacrinites from Lyme Regis, in the British Museum,* 
were prepared in this manner. 
The crinoideal remains in Chalk belong but to few genera ; 
they merely require the usual manipulation of cretaceous 
fossils. The collector, however, should remember that the 
ossicula and plates of the receptacle (as for instance of the 
Marsupites), are but slightly adherent to each other, and the 
chalk must not be wholly removed, or these parts will be- 
come detached. 
The receptacles of the Apiocrinites of the chalk are rarely 
found with more than a few joints of the column attached ; 
and I believe no vestiges of the arms have been observed: 
these parts are therefore desiderata, and should be diligently 
sought for: the radicles of these crinoideans are long, articu- 
lated, and branching, and without due caution may be mis- 
taken for the arms, or for another species. The first remark 
will also apply to the Marsupite; any specimens with but a 
few ossicula of the arms are very precious. I may observe 
that there is yet much to learn as to the number of species 
and genera, and the peculiar characters of the Crinoidea of 
the chalk, and that any addition to our knowledge on this 
subject will be valuable. 
The Asteride are so simple in form and structure, that it 
* Petrifactions, p. 78. 
