For reasons that are not clear, the will of Mimken Habben failed to nominate an executor in 1876. After his death a year later, the will was approved and his widow was appointed administrator with the will annexed. The difference usually is in title only–the job’s pretty much the same as an executor.
In other cases an executor named in a will refuses to act or is unable to act. In those situations an administrator with the will annexed is named as well.