Position of neuronal cell bodies innervating segmental cephalic appendages in the onychophoran Euperipatoides rowelli. Differential staining by retrograde fills with dextran. Confocal projections. Scale bars: 50 μm. (A) Antennal nerve (an) filled with dextran-tetramethylrhodamine. Note the antero-median position of neuronal cell bodies (arrow) within the protocerebral brain region. Anterior is in the upper right corner. (B) Partial projection of the same stack as in A showing that some filled axons of the antennal nerve terminate in the antennal glomeruli (ag). (C) Detail of a jaw nerve (jn) filled with dextran-tetramethylrhodamine. (D) Detail of slime papilla nerves (sn) filled with dextran-fluorescein. Arrowheads indicate the position of neuronal cell bodies in C and D. Abbreviations: ag, antennal glomeruli; an, antennal nerve; ey, eye; jn, jaw nerve; nc, nerve cord; sn, slime papilla nerves.