The development of the four protective layers of the apple, namely the hairs, cuticle, epidermis and hypodermis, is described in detail, from the time the flower emerges from the winter bud early in May, until harvest time early in October. The gradual loss of living and active cell contents is recorded for each layer. Measurements of cuticle thickness for the period of the study are listed and an approximate date is given for each stage of development. The descriptions of tissue morphology are supplemented by ten illustrations.