<big><center>[[Avian Digestive Tract - Anatomy & Physiology|'''BACK TO THE AVIAN DIGESTIVE TRACT''']]</center></big>
<big><center>[[Avian Digestive Tract - Anatomy & Physiology|'''BACK TO THE AVIAN DIGESTIVE TRACT''']]</center></big>
+
+
==Introduction==
+
+
In avian species, the [[Lips - Anatomy & Physiology|lips]] and [[Cheeks - Anatomy & Physiology|cheeks]] are replaced by the [[Skin - Anatomy & Physiology#Cutaneous Appendages#Beak|beak]]. The beak is an area of dense, horny skin overlying the incisive bones of the mandible.
+
+
No modern birds possess teeth, however rudimentary enamel organs have been discovered in the embryos of some birds.