Me. Rev. Stat. tit. 18-C, § 1-508

When a register is unable to perform or neglects the duties of the office, the judge shall certify the register's inability or neglect to the county treasurer, the time of the commencement and termination of the inability or neglect and the name of the person who has performed the duties for that time period. The treasurer shall pay the person named by the judge a salary in proportion to the time that the person has performed the duties of the register and the amount must be deducted from the register's salary.