quamvis.. . probarem, however much I might approve: probarem is used instead of probem on account of the tense of commemorarem (cont. to fact). That probarem itself is not cont. to fact is shown by ut probo.
quotus . . . quisque, how many (see Vocab.).
partibus, party.
crudelitate: because the younger Tubero was sick at the time and needed to be put on shore.
ad eos ipsos, construed with partibus: ยง 280, a (182, a); B. 235, B, 2, c; G. 211, R.1; H. 389, 1 (636, iv, 4); H.-B. 325, 631, 6.