Section 89. The justices of the superior court from time to time may appoint one or more clerical assistants, removable at the pleasure of the justices, and fix their compensation, which shall be paid by the county, or the commonwealth, or by both in such proportion as the justices may determine. The justices may make regulations not inconsistent with law relative to the assignments, duties and service of such clerical assistants, and any other matters relative to them.