Source reference required on polychaete species brain

Alan Hendrickson engram at
Tue Nov 5 16:37:12 EST 1996

Polychaete brains - I should mention that this is not my field. I'm
writing a book on learning and memory (provisional title The Engram)
which I hope to finish sometime in 1997. I came across a reference in an
older edition of the Encyclopedia Britannica which mentioned (in the
macropaedia section on the Nervous System) that many polychaete species
had only two cephalic structures; roughly, a hindbrain and a midbrain,
and that other polychaete species had three cephalic structures; hind-,
mid-, and forebrain. What was interesting (the EB said) was that the
species with the forebrain were all predatory, but the others were
merely prey; a perfect or near perfect association of forebrain ->
predator. Does anybody happen to know the original reference? (Or, since
the same information is not in the current EB, is this still thought to
be the case?) If this association is in fact true, it may have quite
important implications, as it provides a clue to the raison de etre
for the development of the third cephalic structure.

Thanks in advance for any help you can give me on this. Please send
correspondence to me at     engram at
Alan Hendrickson

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