Chitons are a group of molluscs that inhabit the intertidal and subtidal regions, and are called Polyplacophora because they bear many plates on their back.

Kingdom: Animalia
Phylum: Mollusca
Class: Polyplacophora
Order: Neoloricata
Family: Acanthochitonidae
Genus: Cryptochiton
Species: stelleri


These eight overlapping plates are a distinctive characteristic of all chitons, and are usually visible on the chiton's back. When viewed from the bottom, there is a large central foot used for creeping and adherence to the substrate. The head is found in front of the foot, but really only consists of a short squat protuberance with the mouth at the tip.





The gumboot chiton is one species of chiton that is a little different from the rest; it is the largest species of chiton in the world, growing up to 30 cm in length - and its eight plates are covered up by thick, leathery, brick-red flesh so we cannot see them.

The broad and flat foot on the front of the chiton functions in adhesion as well as locomotion. Chitons creep slowly in the same manner as snails – by waves of muscular activity along the foot, called "pedal waves". The division of their shell into eight plates helps them to adhere to the sharply-curved surfaces of the rocky intertidal.


Gumboot chitons, like many molluscs, posses a feeding structure known as a radula. The radula is a firm band made out of chiton (a hard organic material) with two rows of sharp teeth that are scraped over a surface to pick up bits of the food. Gumboot chitons use their radula to eat mainly algae growing on rocks.

Chitons are dioecious, meaning there are female chitons and male chitons. Sperm are released by males into the water and taken up by females. Fertilized eggs are then shed singly or in gelatinous strings. These develop into a trochophore larva, which later metamorphs into the adult form of the chiton.





For more info and picture of chitons, check out these cool sites:

Gumboot chiton information and a video from Race Rocks

check out ""!

Are you ready for the Chiton Quiz?
Test your knowledge of the Polyplacophorans!


J. A. Pechenik. Biology of the Invertebrates, 4th edition. Migraw-Hill Companies, Inc. Toronto, 2000.

R. D. Barnes. Invertebrate Zoology, 5th edition. Saunders College Publishing, Toronto, 1987. 

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