This paper shows that $sn$-metrizable spaces can not be characterized as sequence-covering, compact, $\sigma$-images of metric spaces or $sn$-open, $\pi$, $\sigma$-images of metric spaces. Also, a space with a locally countable sn-network need not to be an $sn$-metrizable space. These results correct some errors on $sn$-metrizable spaces.