ad. In series, one after the other, as opposed to in parallel.
the GNU version of the Collaborative International Dictionary of English
ad. In a series, or regular order; in a serial manner.
The Century Dictionary and Cyclopedia
So as to be serial; in the manner of a series; seriatim. Also seriately.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
ad. in a serial manner
Word Usage
"If what Frank writes is even close to the truth (and his evidence seems overwhelming), George Polk was an impostor diligent in serially misrepresenting his war record."