GALLEY-Worm, in zoology, an insect known by most writers under the name of Isius. It is a land-insect, with a long body, composed of a great number of rings, and furnished with many feet. It is found very frequently in gardens; and, when touched, has the power of rolling itself up into a ball. This animal is very common among us, and is by some referred to the scolopendrae, but improperly: for though they agree in the great number of legs, ours is a harmless animal; whereas the scolopendrae are mischievous creatures, armed with dangerous forceps. It is supposed by Lister, that this sort of animal, common with us, would on distillation yield the same sort of animal-acid that is procured from the ant. The reason of the conjecture is, that the ant and this creature agree in emitting a sharp and pungent smell on being bruised; but these are not easily procured in sufficient plenty to make the experiment, as they are not gregarious like the ants.