In this study, the hypothesis of a possible biogenesis of the ciliary roots is suggested, after observing the cilia neurons under the electron microscope, which were found as an exception in the periaqueductal nucleus of the mesencephalon in the domestic cat, conserving the potential to differentiate the cilia, basal bodies and ciliary roots. The dictyosomes of Golgi’s complex and Golgi’s vesicles participated in this biogenesis. Vesicles of approximately 71.6 nm in diameter had become separated from the periphery of the flattened discoid cisterns of the dictyosome and were aligned normally, in tangential contact with each other, forming rows of vesicles or ‘ringed chains’, whose points of contact formed the beginning of the ‘periodic striation’ of a thin ciliary root. Later, the lateral walls of the vesicles and the molecules of the intracisternal proteins gave rise to the interperiodic microfilaments, when the carrier proteins were transformed into structural proteins of the ciliary roots. The parallel apposition of several ringed chains or thin ciliary roots, with their rings joined at the same level (or transversal striations), gave rise to thicker striated roots. This hypothesis of an ultrastructural biogenesis of the striated ciliary roots involves the following six stages: stage I = separation of Golgi’s vesicles from the periphery of the flattened disk of dictyosomes near the basal body, with a diameter of over 71.6 nm; stage II = reinforcement of the membrane of the vesicles at the two opposite polar ends of its larger diameter; stage III = alignment of vesicles to form ringed chains, due to the tangential contact between their reinforced points; initiation of the 71.6-nm striation period, roots ringed linearly; stage IV = formation of joining microfilaments between periods (69.2 nm) with the lateral walls of the vesicles and the molecules of the proteins in their content; stage V = lengthening of the thin ciliary roots due to the coupling of new Golgi’s vesicles at their ends so that their length increases as a result of the addition of terminal vesicles; stage VI = increase in thickness of the thin ciliary roots, due to the parallel apposition of several ringed chains or thin ringed ciliary roots, at the point where their transversal striation