No abstract

Forty rats served as Ss in an investigation of differential conditioning involving various manners of presentation of the discriminative cues in a runway. For one group of Ss, the cues were presented only in the startbox, while for a second group, the cues were presented in the startbox and during the instrumental response chain. A third group received the cues during the entire instrumental response chain, but only after the start door was raised. A fourth group served as a nondiscriminative control group. The results indicated that the only effects of differential presentation of the discriminative cues were on performance to 8-and that this effect on performance to S-occurred only when stimulus onset coincided with the initiation of the response.

A case of adenocarcinoma involving a müllerian duct cyst is presented. The presentation, treatment, and pathological and radiological appearance are discussed. The embryology and history of this entity are reviewed.