The study and contemplation of the natural world was a significant impetus for the stylistic development of Maurice Ohana's (1913-1992) music. More than any other source, it was the sounds, textures, and patterns of the natural world that served as his compositional model, inspiring a unique approach to form and sound. Using the metaphor of a coral reef, Ohana sought to imbue his compositions with a process of development that organically generated musical form. His mature musical style is defined by an organic development of traits inherent within the motivic beginning of a work to produce unique musical structures that are intrinsically connected with their musical substance. Ohana's final work for piano solo, the Études d'interprétation (1983/6), demonstrate the process of organic development. Complementing Claude Debussy's (1862-1918) Études, Ohana's interval etudes 'Secondes,' 'Quintes,' 'Septiemes,' and 'Neuvièmes' illustrate the stylistic variety generated by his unique, sound-driven approach to form. The following analyses address the thematic development of each work, connecting melodic, harmonic, and textural material to the opening, and developmentally central, `germ' each composition begins with. By examining the comprehensive process of organic development within Ohana's four interval etudes it may be possible to gain a greater understanding of his unique musical language