Notes on the Development of the Neural Crest in the Head of Mus musculus
The relations between the neural crest on the one hand and the neuromeres and their precursors the proneuromeres on the other hand have never been fully described. Many authors have, however, shown that the cranial ganglia lie level with every second neuromere, so that ganglion V lies level with neuromere VII, ganglion VII–VIII level with neuromere IX, and ganglion IX–X level with neuromere XI (Bergquist, 1952). The neuromeres develop in a rostro-caudal wave, which is preceded by a similar wave of proneuromeres—formations of approximately the same appearance but relatively larger (Källén & Lindskog, 1953). The first proneuromere directly corresponds to neuromeres I–II, the second to neuromeres III–IV, the third to neuromere V; and in the rhombencephalon each proneuromere also corresponds to two neuromeres.