Figure 3From: A revision of brain composition in Onychophora (velvet worms) suggests that the tritocerebrum evolved in arthropodsDevelopment of major neuropils in the onychophoran brain. Heads of embryos at progressively older developmental stages in dorsal view. Anti-acetylated α-tubulin immunolabelling. Confocal maximum projections (A, B) and depth-coded projections (C, D). Anterior is up. (A) Central neuropil (cn) arises from a single transverse commissure in the antennal segment in an early Euperipatoides rowelli embryo. Scale bar: 200 μm. (B-D) Further stages of brain development in embryos of Epiperipatus isthmicola. Scale bars: 100 μm. A second transverse neuropil (arrowhead in B) and a third neuropil (arrowheads in C and D) arise anterior to the original commissure. Abbreviations: an, antennal nerve; at, antenna; cn, developing central brain neuropil; jw, jaw anlage; np, future nerve cord neuropil; ph, pharynx; sp, slime papilla.Back to article page