Pentacrinus caput Meduse. 
with the fossil fragments 
described by his predeces- 
sors, and of which he had 
specimens in his collections, 
enabled him to ascertain the 
real origin of the fossil En- 
crinoidee. The beautiful 
fragment of this recent form 
which still exists in the Mu- 
seum of Natural History at 
Paris was long considered 
unique, but it is now known 
that many others exist in 
the different museums of 
Europe and America. Since 
that date the Crinoideze 
have beenexaminedand de- 
scribed by observers such as 
Miller, Forbes, d’Orbigny, 
Agassiz, Sars, Pictet, Major 
Austin, and by Carpenter 
and Wyville Thomson. 
Among the species of 
fixed Crinoidez actually 
living are Pentacrinus 
caput Meduse (Fig. 106) 
and Rhizocrinus lofotensts. 
These curious  Echino- 
derms resemble a flower 
borne upon a stem, which 
terminates in an organ 
called the calyx, which is, 
properly speaking, the body 
of the animal. Arms, more 
or less branching, spring 
from this calyx, their ramifi- 
cations, so formed, con- 
sisting of many pieces arti- 
culated to each other. The 
CRINOIDES. 265 
The comparison of the living individual 
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Fig. 106,—Pentacrinus caput Medusz (Miller). 
calyx is supported by a stem, varying in height, formed of pieces 
secreted by the living tissues which surround them. The articulations 
