Now in their fourth decade of making old-fashioned Cajun music, Michael Doucet and company still muster the freewheeling enthusiasm of eager rookies. As funky as R&B and fiery as punk rock, Alligator Pursestakes out familiar Louisiana turf with Doucet’s flying fiddle and Jimmy Breaux’s wonderfully wheezy accordion. The sextet doesn’t always stick close to home. From “Rouler et Tourner,” a bluesy Muddy Waters cover, to the country wail of “Little Darlin’,” featuring Natalie Merchant, to the foot-stomping “The Problem,” written by swamp-guitar hero J.J. Cale, BeauSoleil’s greasy, soulful grooves guarantee bon temps.