Complex sentence: The pieces, he says, may be taken either from the same poet, or from severa; and the verses may be either taken in their entirity, or divided into two; one half to be connected with another half taken elsewhere.
Split into simpler sentences: The pieces, he says, may be taken either from the same poet, or from several. The verses may be either taken in their entirity, or divided into two; one half to be connected with another half taken elsewhere.