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Re: Time Line
> > > First rudists
> An early group of corals, rather different than the living hexacorals.
> > > First grazing echinoids
> Echinoids are starfish, sea-lilies, sea-cucumbers, sea-urchins
> and so on. The earliest ones were rather like sea-lilies, and
> probably were what is known as filter feeders (a "passive" sort
> of feeding). Later forms, including most living forms, use a
> more active form of feeding, involving searching for food - that
> is the "grazing" forms and the even more derived carnivorous
> forms, such as starfish.
> [Ack, or are echinoids a *sub*group of the echinoiderms??].
In this sense.....Sea urchins.
Curator of Palaeontology
University of Glasgow
Some large dinosaurs had three horns and were called
triceps, others had two horns and were called biceps.
(Geological Howlers - ed. WDI Rolfe)