A more thorough explanation:

Seriatim

Seriatim means doing things one after another in a sequence or consecutively. In legal contexts, it refers to a panel of judges giving their opinions one after another.

During the court hearing, the judges gave their opinions seriatim, with each judge speaking in turn.

The committee members voted seriatim, with each member casting their vote one after another.

The examples illustrate the meaning of seriatim as doing things in a sequence or consecutively. In the first example, the judges gave their opinions one after another, in a specific order. In the second example, the committee members cast their votes one after another, without skipping anyone. This shows that seriatim means doing things in a specific order, without any interruptions or deviations.