  In this paper we examine the well-posedness and ill-posedeness of the Cauchy
problems associated to a family equations of ZK-KP-type \[ \begin{cases}
u_{t}=u_{xxx}-\mathscr{H}D_{x}^{\alpha}u_{yy}+uu_{x}, \cr u(0)=\psi \in Z
\end{cases} \] in anisotropic Sobolev spaces, where $1\le \alpha \le 1$,
$\mathscr{H}$ is the Hilbert transform and $D_{x}^{\alpha}$ is the fractional
derivative, both with respect to $x$.
