Cell adhesion molecule with an important role in the development of the nervous system. Involved in neuron-neuron adhesion, neurite fasciculation, outgrowth of neurites, etc. Binds to axonin on neurons (By similarity). Expressed in many postmitotic neurons in 16-36 hours embryos. Little or no expression in the olfactory placode, the anterior lateral line/acoustic ganglia complex, the posterior lateral line ganglion, late-developing hindbrain neurons and some Rohon-Beard cells in the spinal cord. Onset of expression correlates with the initiation of axonogenesis in 16-36 hours embryos. Belongs to the immunoglobulin superfamily. L1/neurofascin/NgCAM family.