An epizootic of myositis and death in pen-reared bobwhites occurred at a hunting club in California. The myositis was caused by myriads of elongate protozoan cysts. The cysts were in various stages of development and when mature, contained spherical zoites 1 μm in diameter. Sinuous compartments were present in all cysts. The walls of the compartments were composed of a material similar to the cyst walls. Mature cysts were filled with blood. The histologic and ultrastructural morphology of the parasite revealed the parasite to be a haemosporozoan. The parasite has numerous similarities to both Akiba caulleryi (Mathis and Leger, 1909) and organisms that cause aberrant leucocytozoonosis in other species of birds. Further studies are needed to determine if the parasite is a part of the normal parasite fauna of quail or if it represents a parasite in an aberrant host.