  Different interpretations of narrow structures at $W\sim 1.68$ and $W\sim
1.72$ GeV observed in several reactions are discussed. It is questionable
whether interference phenomena could explain the whole complex of experimental
findings. More probable hypotheses would be the existence of one or two narrow
resonances $N(1685)$ and $N(1726)$ and/or the sub-threshold virtual $K\Sigma$
and $\omega p$ production (cusps).
