PRONEUROMERES AND NEUROMERES IN THE CEREBRAL TUBE OF TORPEDO OCELLATA

Abstract

During its early development the cerebral tube of Torpedo ocellata is the site of development for at least 2 different serial repetitions of structural patterns (segments). One very early series, a proneuromery, is the formation of 3 proneuromeres rostral to the otic vesicles, a 4th one level with that vesicle, and a 5th one caudal to it. A later series is the development of 12 neuromeres. The present author calls the former proneuromeres A, B, C, D, and E, and the latter neuromeres A1, A2, A3, A4, B1, B2, C1, C2, D1, D2, E1, and E2. Neur A1-A4 include both the telencephalon and diencephalon, neur B1-B25 is the mesen-cephalon, and neur C1-D2 comprises the rhombencephalon.