The ontogeny of the conidia of representative Dermatophyte species has been examined by time-lapse microphotography. The results are summarized in five main conclusions. (i) the genera Microsporum, Trichophyton and Epidermophyton have holoblastic conidium-ontogeny; (ii) the investigated species exhibit polymeristematic development; (iii) delivery of the conidia occurs by means of a special detaching mechanism: consisting in autolysis of a detaching-cell or cells; (iv) the macroconidia have a primary septum; (v)chlamydospores including "gemmae" and "persistent-organs", strikingly similar to the macro- and microconidia as investigated in aqueous preparations, are also formed. The author classifies the dermatophytes into section III of the system of HUGHES and into the group III/C of TURBAKI's system.