noun Zoology.
a tendency in the development of animals to localization of important organs or parts in or near the head.

1860–65; cephal- + -ization

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World English Dictionary
cephalization or cephalisation (ˌsɛfəlaɪˈzeɪʃən)
(in the evolution of animals) development of a head by the concentration of feeding and sensory organs and nervous tissue at the anterior end
cephalisation or cephalisation

Collins English Dictionary - Complete & Unabridged 10th Edition
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Word Origin & History

1864, coined by U.S. zoologist James D. Dana (1813-1895) from Gk. kephale "head" on model of specialization, etc.
Online Etymology Dictionary, © 2010 Douglas Harper
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Encyclopedia Britannica


the differentiation of the anterior (front) end of an organism into a definite head. Considered an evolutionary advance, cephalization is accompanied by a concentration of nervous tissue (cephalic ganglion or brain) in the head region that serves to integrate the activities of the nervous system. Some groups of organisms (e.g., Aschelminthes) show full cephalization, but because their bodies are not divided into distinct trunks and heads, they cannot be said to possess a distinct anatomical head

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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