he > [Mnemon] advance > praise, extol
2 In all his speech, was Silvius his son,
Silvius his > Silvius's
3 Whom having slain, through luckless arrow's glance
Whom > [Silvius] glance > shot (esp. an oblique shot)
4 He fled for fear of that he had misdone,
that > [that which] misdone > done wrong
5 Or else for shame, so foul reproach to shun,
so > [such a]
6 And with him led to sea a youthly train,