Post-labial sensory structures on the cecal worm, Heterakis gallinarum.

Sense organs that lie just posterior to the lips on the sides of the body of Heterakis gallinarum have been examined by scanning and transmission electron microscopy. The sense organs appear externally as a short peg surrounded by a collarlike elevation of cuticle. Each sense organ contains the endings of 2 sensory dendrites; 1 extending to the tip of the peg is probably chemosensitive, while the other ending just within the cuticular cylinder that projects internally from the peg, is probably mechanosensitive.