Though much of the World Saxophone Quartet's music has been mindful of the contributions of founding member Julius Hemphill, it is on Requiem for Julius where that debt is acknowledged formally.

There are the obligatory R&B, straight blues, or bebop lines here and there, but it's mainly the collective improvisational expertise of John Purcell, David Murray, Oliver Lake, and Hamiet Bluiett pushing the envelope of structure, rhythm, and tonal timbres.

Alto saxophonist Lake's sour sound is as much his own as it is influenced by Hemphill, and he composed three selections that reflect this sonority.

"Le Sport Suite" displays loose, scattershot improvisation and a unison strut in the middle.

"Potato Vamp" is buoyed by Murray's bass clarinet, and is very tunefully contained.

"Tone Poem" perfectly reflects the cadence of spoken word, with its spatially organized phrases arranged in chamber fashion.

Purcell's "All Praise" carries a more sedate, patient, even reverent, improvisational mood.

The Bluiett-penned "Free & Independent Thought" is exactly as the title states, but in a lower-keyed stance.

Murray composed two numbers.

The title track, supported by a processional framework replete with Hemphill's sweet/sour signature, is led by Purcell's soprano sax, sporting a very melodic center with a stretched harmonic edge.

The 11-minute "Hurricane Floyd" is furiously intense, as the quartet tosses in several distinct melody lines throughout.

Also revisited is Jack DeJohnette's "Ebony," with its familiar pussycat traipsing/moaning and juggernaut triple-melody lines.

A long-overdue official farewell for Hemphill, Requiem for Julius not only harkens back to the sound of WSQ's initial recordings, but indicates that they have plenty of original music left in the tank.