neurophysiology - Why are Merkel cells innervated by an axon, and not a dendrite?

Here are two images from Google. Afferent neurons receive input and send it to the central nervous system. Input is received by the neuron's dendritic end and send away centrally via axon terminals that are sheathed with Schwann cells. Axon terminals synapse to motor neurons (muscles and glands).

How is it possible that Merkel cells, which supposed to be a sensory cell, synapse with an axon, and not with a dendritic end?