1 General Introduction.- 2 General Description of the Torus and Commissural Connections.- 2.1 Introduction.- 2.2 Material and Methods.- 2.3 Results.- 2.4 Discussion.- 2.4.1 Torus Superlamination and the T Unit System.- 2.5 Summary.- 3 Connections with the Posterior Lateral Line Lobe.- 3.1 Introduction.- 3.2 Material and Methods.- 3.3 Results.- 3.3.1 Injections in the Posterior Lateral Line Lobe.- 3.3.2 Injections in the Torus.- 3.3.3 Projections to the Nucleus Praeeminentialis Pars Lateralis and Pars Medialis.- 3.4 Discussion.- 3.4.1 The Posterior Lateral Line Lobe-Toms Loops.- 3.4.2 Possible Roles of Feedback of the Descending Electrosensory Pathway.- 3.4.3 Interconnection of Posterior Lateral Line Lobe and Toral Layers.- 3.4.4 A Temporal Comparator in the Torus.- 3.5 Summary.- 4 Connections with the Mesencephalic Tectum.- 4.1 Introduction.- 4.2 Material and Methods.- 4.3 Results.- 4.3.1 Injections of the Tectum.- 4.3.2 Injections in the Torus.- 4.4 Discussion.- 4.4.1 Vertical Overlap of Inputs with Other Modalities.- 4.5 Summary.- 5 Connections with the Cerebellum.- 5.1 Introduction.- 5.2 Material and Methods.- 5.3 Results.- 5.4 Discussion.- 5.5 Summary.- 6 Connections with the Medial Octavolateralis Complex and with the Reticular Formation.- 6.1 Introduction.- 6.2 Material and Methods.- 6.3 Results.- 6.4 Discussion.- 6.5 Summary.- 7 Concluding Remarks.- 7.1 Organizational Frame of the Torus.- 7.2 Ascending Outputs of the Torus.- References.