SYSTEMATIC 
ARRANGEMENT OF ECHINODERMS. 
CLASS IV. 
ECHINODERMATA. 
ANIMALS with integument: coriaceous, often calcareous; with 
distinct nutrient canal, freely suspended in an abdominal cavity. 
Organs of circulation and generation conspicuous; sexes nearly 
always distinct. Disposition of the organs most frequently quinary, 
with body mostly radiate or globose, in some cylindrical. Distinct 
vestiges of a nervous system, a ring for the most part surrounding 
the mouth and sending off nerves radially. 
OrveErR I. Pediculate Echinoderms. 
Tentacles numerous, membraneous, contractile, terminated by a 
suctorial disc, and issuing from minute apertures in the integument. 
Family I. Crinotdea. Integument calcareous (external skele- 
ton). Rays articulate, supplied with a central canal, absent in 
some. Mostly two apertures of the nutrient canal. 
The name Crinoidea, given by Mittxr to this division of the ani- 
mal kingdom, is derived from xpivoy,a lily. At the beginning of the 
last century the name sea-lily, stone-lily was given to the Encrinus 
monirformis, or liliiformis, a remarkable petrifaction of the Muschel- 
kalk. Most of them are set upon a stem ; the non-pediculate (Coma- 
tula Lam.) in the young state, according to the observations of 
THompson, are also fixed to a pedicle. The non-pediculate species 
known to Linnaus were placed by him in the genus Asterias (Aste- 
rias pectinata, Ast. multiradiata); the pediculate species in the 
