|Matter within parentheses, dashes, or brackets within a
sentence does not begin with a capital letter or take a period, even if
it is a complete sentence in itself. However, it may be followed by a
mark of interrogation or exclamation, and direct quotations may start
with a capital letter:
We walked (there were no horses) across the island.
We walked across the island. (There were no horses.) Then we came. . . .
The key to these twin riddles (why did they carve the statues? why did they stop?) still lies buried here
... high evangelical hopes ("There's a good sermon in this")
The opening and closing parenthesis should be the same typeface; use
roman unless everything within the parentheses is in italics:
behavior of Argentine ants (Linepithema humile)
matter within parentheses is inserted where a comma belongs, the comma
follows the second parenthesis:
After the ball ended (we went home at
five), the islanders ...
Descending slowly (below), Alvin explores ...
When quotes are interrupted by parenthetical matter, use brackets, not
"These men [Greg McGruder pointed to four aides] are
answering questions from the public."