  We present HST images of 24 confirmed members of the distant galaxy cluster
Cl0016+16 at redshift 0.55. The Balmer-strong (``E+A'') and emission- line
galaxies frequently show unusual visual morphology, implying that galaxian
interactions produce ``active'' galaxies in moderate-redshift clusters. We use
the image concentration index as a quantitative measure of morphology to show
that these unusual galaxies appear disklike, while the normal red galaxies
resemble E/S0s. Although consistent with HST observations by Dressler et al. in
Cl0939+4713 ($z=0.41$), our results differ from the Couch et al. finding that
most Balmer-strong galaxies in AC114 ($z=0.31$) resemble ellipticals. The
entire ``E+A'' sample is small, but if future studies confirm their diversity,
it will suggest that they have different origins.
