Nose, the external organ containing the nostrils and connected with the sense of smell.  Many lower animals possess the power of smell but have no nose.  The nose proper begins in the vertebrate animals.  The nostrils serve as paths for air into the respiratory passages.  They lead also into the chamber of the nose, which is divided by a fiat bony partition into right and left sides.  The walls of each cavity are convoluted (turbinated bones), and covered with a soft membrane from which the nerves of smell pass to the brain.  The sense-cells, which are especially modified for smelling, are located in the membrane, and the nerve fibers forming the olfactory nerve grow from them.  The olfactory nerve usually enters into an olfactory lobe before making connection with the brain.