37 CFR 41.45: Appeal forwarding fee.

(a) Timing. Appellant in an application or ex parte reexamination proceeding must pay the fee set forth in § 41.20(b)(4) within the later of two months from the date of either the examiner's answer, or a decision refusing to grant a petition under § 1.181 of this chapter to designate a new ground of rejection in an examiner's answer.

(b) Failure to pay appeal forwarding fee. On failure to pay the fee set forth in § 41.20(b)(4) within the period specified in paragraph (a) of this section, the appeal will stand dismissed.

(c) Extensions of time. Extensions of time under § 1.136(a) of this title for patent applications are not applicable to the time period set forth in this section. See § 1.136(b) of this title for extensions of time to reply for patent applications and § 1.550(c) of this title for extensions of time to reply for ex parte reexamination proceedings.