SUB-KINGDOM III.--ANNULOIDA.
Animals in which the digestive canal is completely shut off from
the cavity of the body; a distinct nervous system; a system of
branched "water-vessels," which usually communicate with the
exterior. Body of the adult often "radiate," and never composed
of a succession of definite rings.
CLASS I. ECHINODERMATA.
_Order_ 1. _Crinoidea_ ("Sea-lilies"). _Ex_.
Feather-star (_Comatula_), Stone-lily (_Encrinus_*).
_Order_ 2. _Blastoidea_* ("Pentremites").
" 3. _Cystoidea_* ("Globe-lilies").
" 4. _Ophiuroidea_ ("Brittle-stars"). _Ex_.
Sand-stars (_Ophiura_), Brittle-stars (_Ophiocoma_).
_Order_ 5. _Asteroidea_ ("Star-fishes"). Ex. Cross-fish
(_Uraster_), Sun-star (_Solaster_).
_Order_ 6. _Echinoidea_ ("Sea-urchins"). Ex. Sea-eggs
(_Echinus_), Heart-urchins (_Spatangus_).
_Order_ 7. _Holothuroidea_ ("Sea-cucumbers"). _Ex_.
Trepangs (_Holothuria_).
CLASS II. SCOLECIDA** (Intestinal Worms, Wheel Animalcules, &c.)
SUB-KINGDOM IV.--ANNULOSA.
Animal composed of numerous definite segments placed one behind
the other; nervous system forming a knotted cord placed along
the lower (ventral) surface of the body.
_Division A. Anarthropoda_. No jointed limbs.
CLASS I. GEPHYREA** ("Spoon-worms").
CLASS II. ANNELIDA.
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