A colleague has found something he believes are spines of Jurassic echinids.
The only reference he's used so far is the relevant volume of the Treatise.
Could anybody point him to more recent references (preferably in English) on
echinids, particularly something dealing with anatomy/morphology and
environmental constraints (salinity, water depth, temperature)?
Thanks in advance, Florin
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Florin Neumann
florin@quartz.geology.utoronto.ca