One of the most striking aspects of Musorgsky's scores is the frequent use of seemingly strange orthography.* It is by no means unusual to encounter peculiarities of pitch spelling in his music which are hard to reconcile with the more standard concepts of tonal structure. Inevitably, these peculiarities raise questions about their particular significance and about Musorgsky's intellectual self-awareness. On a broader plane, Musorgsky's notations supply rich pickings for those interested in the broader analytical significance of orthography. The notion that notation might hold a key to our perceptions of Musorgsky's compositional ability on a 'technical' level is first hinted at by the apparent rather than real alterations made by Rimsky-Korsakov in his editions of Musorgsky's works. In addition to the wholesale rewriting of passages, Rimsky-Korsakov made frequent amendments to pitch spelling without any resultant change to pitch content.' Such alterations signify a difference in tonal thinking between Musorgsky and his first editor a predictable difference, given Rimsky-Korsakov's increasingly academic (read 'German') musical orientation at the time he created these editions. The critical validity of Rimsky-Korsakov's editorial intervention is now generally discredited and his versions are seen in historical perspective as flawed performing editions (which nevertheless achieved much in establishing a number of Musorgsky's works in the musical canon). This leaves the irregularities the 'mistakes' corrected by Rimsky-Korsakov of Musorgsky's original scores to be considered for what they are: valid, vivid imprints of the composer's tonal thought. While these imprints fall into a wide range of categories, the present article focuses on orthography, taking as a case study two closely related pieces from Pictures at an Exhibition: 'Catacombae' and 'Con mortuis in lingua