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4 Chemotactic Cell Motion and Biological Pattern Formation
70

A study on the formation of crocodile skin, discussing the origin of the
pigmentation pattern, can be found in [13].
Is has been conjectured in the biological literature that the formation of
tortoise shells is based on a chemotactic process, responsible for the lateral
growth of the ribs, which then undergo ossification. We refer to [14].
The Images 4.1–4.5 were shot in South Africa and Namibia, 4.6 in the Mex-
ican province Chiapas, 4.7 in northern Queensland (Australia) and 4.8 on the
Galapagos Islands (Ecuador).

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