The behaviour and neuro-anatomy of some developing teleost fishes

This investigation relates the ontogenetic development of observable behaviour to theunderlying co-ordinating and conducting systems in telecosts. It is based on a study of the eggs of seven species, fertilized artificially. The onset of behaviour was marked by the heart beat; this started in separate regions which became connected and developed a rhythm. It was followed by non-rhythmic contractions of the body musculature, the resulting flexures becoming alternating or serial and cephalo-caudal. Movements of the pectoral fins, jaws and opercula were first performed as part of the axial musculature of the body; later they became independent and co-ordinated. There was an increasing tendency towards stability and efficiency in the development of response to tactile, chemical, vibrational, feeding, rotational and light stimulation.