adjective Chiefly Zoology, Anatomy.
Examples from the Web for extensile
It has an excessively long, slender muzzle, and a worm-like, extensile tongue.Oregon and Eldorado|Thomas Bulfinch
The tongue is long and extensile, and is much attenuated towards the tip, where it is covered with strong and recurved papillae.The Cambridge Natural History, Vol X., Mammalia|Frank Evers Beddard
There are no teeth; and although the tongue is long and worm-like, it is not extensile.
It is really astonishing to see what large morsels they can dispose of with the assistance of their extensile mouths and stomachs.The Sea Shore|William S. Furneaux
The only other North American birds that have a tongue built upon this plan are the hummingbirds, in which also it is extensile.The Woodpeckers|Fannie Hardy Eckstorm