Most of the caterpillars have oval, slug-shaped, smooth bodies, with the under surface flattened, and very small heads, which in many species can be extended by means of an extensile neck.
"Butterflies Worth Knowing"
Clarence M. Weed
It is capable of swallowing a worm of thrice its own size: this circumstance, though it may appear incredible, is easily understood, when we consider that the body of the polype is extremely extensile, and is dilated, on such occasions, to a surprising degree.
"Illustrative Anecdotes of the Animal Kingdom"
Samuel Griswold Goodrich
The Indian tapir has a more powerful and extensile trunk than the American, and its skull shows in consequence a greater space for the attachment of the muscles.
"Natural History of the Mammalia of India and Ceylon"
Robert A. Sterndale