ECHINODERMS

GENERAL CHACTERISTICS

-Characterized by their water vascular system

-Also characterized by an array of canals, bladders, and tubelike processes

-This contols their locomotion, respiration, and prey capture

-Calcitic skeleton is present

CLASSIFICATION

-The Echinderms are classified into four subphylums

1. Subphylum Asterozoa
2. Subphylum Echinozoa
3. Subphylum Crinozoa
4. Subphylum Blastozoa

Each Subphylum is then classified into classes

1. Subphylum Asterozoa
   • Class Asteroidea
   • Class Ophiuroidea

      2. Subphylum Echinozoa

• • Class Echinoidea
  • Class Holothuroidea
  • Class Edrioasteroidea
  • Class Ophiocistoidea
  • Class Helicoplacoidea
  • Classes Cyclocystoidea and Edrioblastoidea

     3. Subphylum Crinozoa

• • Class Crinoida

      4. Subphylum Blastozoa

• • Class Blastoidea
  • Class Rhombifera
  • Class Diploporita
  • Class Eocrinoidea
  • Class Parablastoidea
  • Class Paracrinoidea

SPECIMINS

1. This specimin is a part of a crinoid stem which is part of the Subphylum Crinozoa and is in the Class Crinoida.

ILLUSTRATION OF LIVING CRNOID