blastoidea

from The Century Dictionary.

• A group of fossil pelmatozoan echinoderms without arms, with ambulacra fringed on each side by pointed appendages in close relation with side-plates, which rest on or against a subambulacral lancet-plate pierced by a canal which lodges a water-vessel, and with hydrospires arranged in 10 or 8 groups limited to the radial and inter-radial plates.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) One of the divisions of Crinoidea found fossil in paleozoic rocks; pentremites. They are so named on account of their budlike form.