The U.S. FWS and the NMFS propose to revise portions of their regulations that implement section 4 of the Endangered Species Act of 1973, as amended (Act). The proposed revisions to the regulations clarify, interpret, and implement portions of the Act concerning the procedures and criteria used for listing or removing species from the Lists of Endangered and Threatened Wildlife and Plants and designating critical habitat. Multiple technical revisions are also proposed to update existing sections or to refer appropriately to other sections. Comments will be accepted from all interested parties until 24 September 2018. POC is Bridget Fahey, U.S. FWS, Division of Conservation and Classification, 5275 Leesburg Pike, Falls Church, VA 22041-3803, tel: 703-358-2171; or Samuel D. Rauch, III, NMFS, Office of Protected Resources, 1315 East-West Highway, Silver Spring, MD 20910, tel: 301-427-8403 (Federal Register; 25 July 2018 [Proposed Rules], pages 35193-35201).