436 The unripe fruit of an unready wit:

wit > mind, intelligence

437 Which by your countenance does crave to be 438 Defended from foul Envy's poisonous bit.

bit > {Bite, the action of biting}

439 Which so to do may you right well besit,

right > very besit > become, befit

440 Sith the antique glory of your ancestry

Sith > Since
antique > ancient

441 Under a shady veil is therein written, 442 And eke your own long living memory,

eke > also