Tonicella lineata’s Fine Lines

When I show images of chitons I always want to ask, “do you know which way the head is pointing?” Today I’ll refrain because I want to talk about the fine lines of Tonicella lineata. Just about everybody knows T. lineata as the lined chiton. The wavy bluish-white lines on the shell are eye-catching and the specific epithet, lineata, shows that William Wood agreed when he put together the original combination, Chiton lineatus, in 1815.


Julia Sigwart suggests the lines may combine with blocks of color on the shell and girdle to create disruptive contrast camouflage, a protection against visual predators. She wrote about it in The chiton stripe tease. Her title is gold. What do you think about the camouflage hypothesis?

If you crave more chitons, or just want to test your ability to discern which way the head is pointing, go to my Chitons page where you’ll find more Tonicella lineata and other common chitons from Oregon’s exposed rocky shores.


Sigwart, J. D. (online, October 2016). The chiton stripe tease. Oceanarium. Open access at

Coan, E. V. and R. E. Petit. 2011. The Publications and Malacological Taxa of William Wood (1774–1857). Malacologia, 54(2):1-76.