  A recent experiment by Ma and collaborators shows that the gap anisotropy in
${\rm Bi}_2 {\rm Sr}_2 {\rm Ca}_1 {\rm Cu}_2 {\rm O}_{8+x}$ is strongly
temperature dependent. In particular, the superconducting gap along the $\Gamma
- M$ direction shows a weaker temperature dependence than the gap along the
$\Gamma - X$ direction which decreases rapidly with temperature. We explain
this novel feature as a natural consequence of the interlayer tunneling
mechanism of superconductivity.
