  In the theory of Hilbert $C^*$-modules over a $C^*$-algebra $A$ (in contrast
with the theory of Hilbert spaces) not each bounded operator ($A$-homomorphism)
admits an adjoint. The interplay between the sets of adjointable and
non-adjointable operators plays a very important role in the theory. We study
an intermediate notion of locally adjointable operator $F:M \to N$, i.e. such
an operator that $F\circ g$ is adjointable for any adjointable $g: A \to M$. We
have introduced this notion recently and it has demonstrated its usefulness in
the context of theory of uniform structures on Hilbert $C^*$-modules. In the
present paper we obtain an explicit description of locally adjointable
operators in important cases.
