Assertion: actinia | /r/HasProperty | the mechanism
Facets:
Source sentences:
text: After the account above given of the general structure of the Actinia, the mechanism whereby the tentacula are expanded and withdrawn will be easily understood: these do not, like the horns of a snail, become inverted and rolled up within the body, but owe their different states of extension entirely to the forcible injection of water into their interior.