nounusually tube feet
(in an echinoderm) each of a large number of small flexible hollow appendages protruding through the ambulacra, used either for locomotion or for collecting food and operated by hydraulic pressure within the water-vascular system.
- ‘We demonstrate that there is considerable variation in tube-foot morphology among members of the Asteroidea including an entirely new type of flat-tipped, non-suckered tube foot in species belonging to the order Valvatida.’
- ‘Scanning electron microscopy revealed that the tube feet of Acodontaster conspicuus lacked suckers, with no distinct concavity in the center of the disc, as seen in a typical flat-tipped suckered tube foot.’
- ‘Each tube foot is made of an ampulla, podium, and usually a sucker.’
- ‘Each canal has a lateral connection which leads to a tube foot, which may be composed of three parts.’
- ‘This indicates that considerable morphological change occurs in the post-juvenile tube foot.’
We take a look at several popular, though confusing, punctuation marks.