fter only a few minutes of Perú Negro's performance at Town Hall on Saturday night, you understood why one of the principal Afro-Peruvian musical and dance forms is called the festejo. That word, a program note explained, is derived from festejar, meaning "to celebrate or have a good time." This was more than two hours of celebration, and those two hours added up to be a very good time.

Perú Negro, which was presented by the World Music Institute, was founded in Lima in 1969. It is directed by Ronaldo Campos, known as Rony, the son of the its first director, also named Ronaldo, who died in 2001. The group seeks to preserve what is known of the cultural traditions of blacks who first came to Peru as slaves in the 18th century and to continue to develop those traditions in new ways. Many of the dances in what was essentially a musical and choreographic revue emphasized strong thrusts forward, the body expanding and contracting in bursts of energy. There were also many quick quivers and shakes; solid earthbound steps were occasionally contrasted with brisk little hops.

Live music was provided by singers, percussionists and guitarists, who also did their own rhythmic dancelike movements. Musicians often swayed as they sang and played. A work for seven men playing the cajón could easily be called music that danced. The cajón is a wooden box that is beaten by someone sitting atop it and hitting its sides. It had its origin in the 1700's when slaves were prohibited from using actual drums. (Drums, though, are now part of the Perú Negro ensemble.)

In "Cajónes Samba Malató" seven cajón players raised and lowered their arms and hands in precisely choreographed patterns and punctuated their drumming gestures by clapping their hands and bending down to slap their legs.

A few pieces belabored their points, among them two comic sketches: one about a creaky old dancing master and his impudent young students and another about some rival tap-dancers. But even though their comedy threatened to turn leaden, the tap-dancers, solidly built, were remarkably nimble on their feet.