Transmission electron micrographs (TEM) showing the organization of microtubular roots that originate from the dorsal and ventral basal bodies (DB and VB, respectively). Those are viewed from the anterior end (A-F at same scale, bar = 500 nm). A. The proximal region of the basal bodies close to the cartwheel structure. The dorsal root (DR) originates from the DB; the intermediate root (IR) and the ventral root (VR) extend from the VB. A dorsal lamina (DL) attaches to the dorsal side of the DR; the right fiber (RF) is close to the ventral side of the VR. B. Section showing the right fiber (RF), the IR-associated lamina (IL), a left fiber (LF) and an intermediate fiber (IF) associated with the VB. The arrow points to the connective fiber between the DB and the VB. Dense fibrils (double arrowhead) extend to the right side of each microtubule of the intermediate root (IR). C. Section through the middle part of the DB and the VB. D. Section through the insertion of the flagella. E. Section through the flagellar transition zone showing the extension of the DL and disorganization of the VF. F. Section showing the linked microtubules (LMt) associated with the dorsal lamina (DL) and the ventral root (VR). G. High magnification view of proximal area of the two basal bodies, the DB and the VB, of A showing the cartwheel structure and the dorsal lamina (DL) on the dorsal side of the dorsal root (DR). The double arrowhead indicates the fibril from each microtubule of the IR. H. High magnification view of right wall of the pocket of F showing the LMt and the DL. I. High magnification view of the IR of D showing the relationship among the IR, IL and IF. J. High magnification view of the IR at the level of E showing the IR and IL. K. High magnification view of the IR and IL. L. High magnification view of the VR in E. (G-L, bars = 200 nm).