Comment from SL via DP:
“Victor's file sheet for this session shows the instrumentation as 2 cornets; 2 trombones; French horn; 3 saxes; piano; banjo; guitar; string bass; drums.
While a French horn isn't heard on this session, three trumpets are, each of whom solos, Williams on all four titles, Whetsel on Mississippi and Jenkins on The Duke Steps Out.
(So add Jenkins to the personnel on this session.)”