Collier's New Encyclopedia (1921)/Blastoidea
BLASTOIDEA (so called from their oval or globular form, like that of a bird), an order of echinoderms, called also pentremites. They are found only in Palæozoic rocks.
Edition of 1921; disclaimer.
BLASTOIDEA (so called from their oval or globular form, like that of a bird), an order of echinoderms, called also pentremites. They are found only in Palæozoic rocks.