The Wolf Trap Opera Company ended its brief but eventful season yesterday afternoon at the Meadow Center with two hours of individual and collective showing-off.

The theme was French music -- announced from the beginning, when conductor Richard Woitach and the orchestra launched into "La Marseillaise," a performance that brought the audience to its feet chuckling and, in some cases, singing along. A program of French operatic highlights followed, which were calculated to demonstrate the exceptional quality of the 19 singers who have worked at Wolf Trap this summer. Performances were competent throughout and sometimes dazzling.

This season, Wolf Trap has presented operas from the traditions of Vienna (Mozart's "Cosi fan tutte" and Haydn's "The Apothecary"); Poland (Szymanowski's "King Roger") and the United States (Blitzstein's "Regina.") This may leave devotees of Puccini feeling deprived, but it served well to balance the overall musical diet of the Washington area and gave the singers some rare experience.

The final French program broadened that experience still further, venturing into what is (for American singers) probably the most elusive of the major operatic idioms. The afternoon had some spectacular individual highlights, but above all it was a collective showcase, putting the emphasis on ensemble singing and the strength of the company as a whole.

It was a particularly good afternoon for mezzo-sopranos and baritones: Adelle Nicholson, Lynn Beckstrom and Anita Berry among the women; James Dietsch, Robert Ferrier, Nicholas Karousatos, Philip van Lidth de Jeude and Peter Lightfoot among the men -- but it is almost unfair to single out individual names in a group that was so ensemble-oriented. If the showcase is considered a competitive event, some singers were given a definite edge by having show-stopping solos assigned to them -- including Nicholson, Ferrier, Karousatos, Dietsch (who swaggered marvelously in Bizet's "Toreador Song"), Lightfoot and tenor Bruce Ford. But the solo plums were distributed according to ability, and there was no sense of competition among the performers.

The company's spirit of cooperation was demonstrated most graphically, perhaps, in the "Gypsy Song" from "Carmen." Nicholson, as Carmen, shared its three verses with Beckstrom and soprano Virginia Boomer, who were cast in the roles of Mercedes and Frasquita--voices normally heard singing "La, la, la" in the refrain.

The same ensemble spirit prevailed beautifully in the "Carmen" quintet, where the three women's voices were joined by tenor Charles Walker and bass-baritone Lawrence Evans in a very polished and well-balanced performance.

Ensemble was also the chief virtue of the prison scene trio from Gounod's "Faust," sung by soprano Jane Williams (who soloed spectacularly in "Regina" on Friday night), tenor George Gray and bass Joseph Pate. Stylish ensemble singing was also provided by Berry and soprano Debra Vanderlinde in a duet from Delibes' "Lakme" and by Beckstrom and Walker in a duet from Offenbach's "La Pe'richole."

On the whole, the Meadow Center's wild acoustics seemed to have been tamed for this performance, as they also were on Friday night for "Regina" -- perhaps because the stage was framed with enormous velvet drapes that could soak up unwanted reverberations. Still, there were moments when the sound of a flute seemed to emerge from the middle of the audience, and there were some problems with dynamics on the highest soprano notes.

On Friday night, Lisbeth Lloyd, who sang the role of Alexandra in "Regina," seemed to have a rich, beautifully controlled middle register but a rather shrill and overloud upper range. The same problems occurred when she came on yesterday afternoon to sing the role of Gounod's Juliet to tenor Robert Tate's Romeo. The first impression was that she might need to work on control at the top of her range. But a few minutes later, Vanderlinde (who sang the same role in "Regina" on Saturday night) began having exactly the same problem, and suspicion shifted from the voices to the sound system.

There may have been some sonic problems for a few tenors, too, particularly at high dynamic levels, though the evidence seems more clear-cut in the case of the coloratura sopranos. Other voices seemed free of these problems: The baritones, in particular, were rich and clear, the mezzos all came across with strong and well-focused impact, and sopranos who avoided the vocal stratosphere -- Boomer, Williams and Barbara Hocher -- had no problems. Hocher performed spectacularly, in fact, in the St. Sulpice scene from Massenet's "Manon," with silvery tone, fine legato line and a graceful sense of the music's form and style that added up to one of the most memorable moments in the whole program.

But the highlight of the afternoon -- a scene that will haunt me for months -- was the very substantial duet from Act II of Saint-Saens' "Samson et Dalila" as sung by Nicholson and tenor George Gray. Gray, who began his career as a bass and worked his way up to where the prospects of glory are stronger, has brought along the solidity that one associates with the lower male voices. His is a big voice with ringing tone, but also considerable agility, and great long-range potential.

Nicholson has sung often in Washington in the past few years -- often enough to make comparisons possible and to say that she seems has grown significantly during her two months at Wolf Trap. The evidence from her small role in "King Roger" was inconclusive (as much else in that production was), but in Haydn's "Apothecary" and in yesterday's showcase, her voice seemed to have the ingredients of star quality. When it opened up to its full power at the climax of "Mon coeur s'ouvre a ta voix," it was a moment to make one remember -- and then forget -- Rise' Stevens; a moment to put shivers in the spine and tears -- tears of joy -- in the eyes.

The same power reappeared, perhaps a bit less spectacularly, in the "Carmen" excerpts, and it is reinforced by a strong stage presence and considerable acting ability. With proper additional seasoning and deeper experience, this might develop into one of the great talents of the next generation.

But similar promise, in greater or smaller measure, seemed to be present in most of the voices that sang yesterday. This summer's Wolf Trap Opera Company, selected from some 600 applicants, included some of the most exciting young voices in America, and it would be no surprise to see more than half of them go on to significant operatic careers. In some cases, more work needs to be done on one aspect or another of the complex art of operatic performance.

Lightfoot, for example, will benefit from further dramatic training and experience, but his voice has qualities that make it worthwhile for him to continue working hard.

This summer's Wolf Trap Company had its opera house taken away and a tent substituted just before the season opened; to compensate, it had the Barns, an ideal environment for chamber opera, but overall this season must be set down as one of heavy adversity. The spirit with which the company met and overcame this adversity was as impressive as its musical talent.