Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Parablastoidea
Directory
References
Discover
Colorful winter sunset
What's the Difference Between a Solstice and an Equinox?
Coriander leaves, fresh green cilantro on wooden background, herbs
Why Does Cilantro Taste Like Soap to Some People?
Facsimile of one of William Henry Ireland's forgeries, a primitive self-portrait of William Shakespeare(tinted engraving). Published for Samuel Ireland, Norfolk Street, Strand, December 1, 1795. (W.H. Ireland, forgery)
The Time a Law Clerk Successfully Forged a New Shakespeare Play to Impress His Dad
The impeachment trial of Pres. Andrew Johnson, illustration from Frank Leslie's Illustrated Newspaper, March 28, 1868.
What If the President Is Impeached?
King Cobra snake in Malaysia. (reptile)
9 of the World’s Deadliest Snakes
World Data Locator Map: Australia
Is Australia an Island?
Four year old boy with grandfather and father lighting Hanukkah menorah. Photo taken on: December 21st, 2009
Which Is Correct: Hanukkah or Chanukah?

Parablastoidea

fossil echinoderm class

Learn about this topic in these articles:

annotated classification

  • starfishes
    In echinoderm: Annotated classification

    †Class Parablastoidea Lower to Middle Ordovician about 460,000,000–500,000,000 years ago; resemble Blastoidea but differ in structure of ambulacra and in numbers of thecal plates. †Class Rhombifera Lower Ordovician to Upper Devonian about 350,000,000–500,000,000 years ago; theca globular; respiratory structures rhomboid sets of folds or canals.

    Read More