A study has been made of the circular birefringence and circular dichroism of alpha and gamma crystallins obtained from dogfish lenses. The Cotton effects in the optical rotatory dispersion and circular dichroism spectra are correlated with maxima in the electronic absorption spectra. On the basis largely of this correlation, the transitions which give rise to the Cotton effects have been assigned to various chromophores. It is concluded that the secondary structure of these proteins is made up of beta structure and the unordered conformation. Little or no α-helical conformation seems to be present.