  The purpose of the present paper is to investigate some structural and
qualitative aspects of two different perturbations of the parameters of
$g$-fractions. In this context the concept of \emph{gap} $g$-fractions is
introduced. While tail sequences of a continued fraction play a significant
role in the first perturbation, Schur fractions are used in the second
perturbation of the $g$-parameters that are considered. Illustrations are
provided using Gaussian hypergeometric functions. Using a particular gap
$g$-fraction, some members of the class of Pick functions are also identified.
