What is the test for abuse of a district court's refusal to appoint counsel?

This court reviews for abuse of discretion a district court's refusal to appoint counsel. United States v. 30.64 Acres of Land, 795 F.2d 796, 798 (9th Cir.1986). Generally there is no constitutional right to counsel in a civil case. Id. at 801. A district court, however, can designate counsel to represent indigent civil litigants under 28 U.S.C. Sec. 1915(d). Id. at 798. Motions for designation of counsel under section 1915(d) are addressed to the sound discretion of the district court and are granted only in exceptional circumstances. United States v. McQuade, 647 F.2d 938, 940 (9th Cir.1981) (per curiam), cert. denied, 455 U.S. 958 (1982). To decide whether exceptional circumstances exist, a court evaluates "the likelihood of success on the merits and the ability of the plaintiff to articulate his claims in light of their complexity." Wood v. Housewright, 900 F.2d 1332, 1335 (9th Cir.1990).