Initiation of the Spawning Reflex Response in Fundulus by the Administration of Fish and Mammalian Neurohypophysial Preparations and Synthetic Oxytocin

The normal spawning behavior of the killifish, Fundulus heteroclitus (Linn.), has been described by Newman (1907). After a period of active courtship on the part of the male, the two sexes come together in close approximation (Fig. 1). The bodies are flexed in a characteristic FIG. 1. The normal spawning attitude of male and female Fundulus heteroclitus, from Newman (1907). Dorsal and ventral views; female stippled. The straight line indicates points of contact with the side of the aquarium. S-shaped curve, and the genital products are emitted simultaneously during a period of rapid mutual vibration. The S-shaped pattern which, in this